Journal of Magnetism and Magnetic Materials最新文献

{"title":"Effective spin filter and diode based on triple magnetic junction","authors":"M. Wilczyński,&nbsp;K. Zberecki,&nbsp;M. Wierzbicki","doi":"10.1016/j.jmmm.2024.172635","DOIUrl":"10.1016/j.jmmm.2024.172635","url":null,"abstract":"<div><div>The charge current flowing through the triple junction composed of ferromagnetic external electrodes and inner layers of different thickness separated by three non-magnetic barriers is analysed in four colinear magnetic configurations. The thickness of the inner layers and the bias voltage can be set in such a way that the junction can act as a tunnel diode with current flowing effectively in one specific direction. The diode properties of the junction can be adjusted by a change of relative orientation of magnetic moments in the inner layers and electrodes; especially the junction can act as a diode in only one magnetic configuration. Magnetic configuration switching can also reverse the direction of the flow of tunnel current.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"611 ","pages":"Article 172635"},"PeriodicalIF":2.5,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced low field magnetocaloric effect through Fe doping induced ferromagnetic transition in HoCo0.8Fe0.2C compound","authors":"Zhihong Hao ,&nbsp;Xiaojuan Wang ,&nbsp;Yao Liu ,&nbsp;Taosheng Zhong ,&nbsp;Lina Zhang ,&nbsp;Changwang Yuan ,&nbsp;Licheng Xiao ,&nbsp;Hui Liu ,&nbsp;Juguo Zhang","doi":"10.1016/j.jmmm.2024.172632","DOIUrl":"10.1016/j.jmmm.2024.172632","url":null,"abstract":"<div><div>The development of high-performance magnetocaloric materials has garnered significant attention due to their potential applications in magnetic refrigeration technology. Element doping has emerged as a crucial strategy for enhancing the magnetocaloric properties of these materials. In this study, we present the enhanced magnetocaloric effect in the HoCo_0.8Fe_0.2C compound through Fe doping. The Fe doping not only induces a ferromagnetic transition but also significantly improves the magnetocaloric performance of the compound. Under a magnetic field change from 0 to 7 T, the HoCo_0.8Fe_0.2C compound exhibits a maximum magnetic entropy change (<span><math><msubsup><mrow><mo>-</mo><mi>Δ</mi><mi>S</mi></mrow><mrow><mi>M</mi></mrow><mrow><mi>max</mi></mrow></msubsup></math></span>) of 20.5 J/kg K and a refrigerant capacity (RC) of 573.3 J/kg. Additionally, this compound undergoes a spin reorientation transition at 11 K and a ferromagnetic to paramagnetic transition at 18 K. These transitions are critical to understanding the magnetocaloric behavior of the material. The results highlight the potential of Fe-doped HoCo_0.8Fe_0.2C as an efficient magnetocaloric material, contributing to the advancement of magnetic refrigeration technology at low temperatures. Our study underscores the impact of element doping on the magnetic and magnetocaloric properties of intermetallic compounds.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"611 ","pages":"Article 172632"},"PeriodicalIF":2.5,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142587241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic susceptibility and heat capacity of a quasi-spin chain compound, Li2CuO2","authors":"Ashiwini Balodhi,&nbsp;Min Gyu Kim","doi":"10.1016/j.jmmm.2024.172617","DOIUrl":"10.1016/j.jmmm.2024.172617","url":null,"abstract":"<div><div>Magnetization and heat capacity (<span><math><msub><mrow><mi>C</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>) measurements were performed on blade-shaped single crystals of Li<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>CuO<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>, a one-dimensional spin-chain compound synthesized via the flux method. The magnetization and heat capacity measurements confirm a long-range antiferromagnetic transition at <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub></math></span> = 9.3 K. The magnetic susceptibility, <span><math><mi>χ</mi></math></span> with magnetic field applied parallel (<span><math><msub><mrow><mi>χ</mi></mrow><mrow><mo>∥</mo><mi>b</mi></mrow></msub></math></span>) and perpendicular (<span><math><msub><mrow><mi>χ</mi></mrow><mrow><mo>⊥</mo><mi>b</mi></mrow></msub></math></span>) to the spin chain direction (crystallographic <span><math><mi>b</mi></math></span>-axis) is reported. <span><math><mrow><mi>χ</mi><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> measurements reveal anisotropic behavior, with <span><math><msub><mrow><mi>χ</mi></mrow><mrow><mo>⊥</mo><mi>b</mi></mrow></msub></math></span> <span><math><mrow><mo>&gt;</mo><msub><mrow><mi>χ</mi></mrow><mrow><mo>∥</mo><mi>b</mi></mrow></msub></mrow></math></span> in the temperature range <span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub><mo>&lt;</mo><mi>T</mi><mo>&lt;</mo><mn>350</mn></mrow></math></span> K, with a ratio of <span><math><mrow><msub><mrow><mi>χ</mi></mrow><mrow><mo>⊥</mo></mrow></msub><mo>/</mo><msub><mrow><mi>χ</mi></mrow><mrow><mo>∥</mo></mrow></msub></mrow></math></span> = 1.15 at 300 K and with <span><math><msub><mrow><mi>χ</mi></mrow><mrow><mo>⊥</mo><mi>b</mi></mrow></msub></math></span> <span><math><mrow><mo>&lt;</mo><msub><mrow><mi>χ</mi></mrow><mrow><mo>∥</mo><mi>b</mi></mrow></msub></mrow></math></span> at <span><math><mrow><mi>T</mi><mo>=</mo><mn>2</mn></mrow></math></span> K, with a ratio of <span><math><mrow><msub><mrow><mi>χ</mi></mrow><mrow><mo>⊥</mo></mrow></msub><mo>/</mo><msub><mrow><mi>χ</mi></mrow><mrow><mo>∥</mo></mrow></msub></mrow></math></span> = 0.86 at 2 K. Unlike the previous studies reporting ferromagnetic components at low temperatures, we report the absence of a ferromagnetic ordering at low temperatures.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"611 ","pages":"Article 172617"},"PeriodicalIF":2.5,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142587242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural, magnetic, elastic, and thermoelectric properties of Ba2InOsO6 double perovskite in the cubic phase: A DFT + U study with spin-orbit-coupling","authors":"Lakhdar Benahmedi,&nbsp;Anissa Besbes,&nbsp;Radouan Djelti","doi":"10.1016/j.jmmm.2024.172629","DOIUrl":"10.1016/j.jmmm.2024.172629","url":null,"abstract":"<div><div>In this study, we comprehensively investigate the structural, electronic, magnetic, elastic, and thermal properties of the double perovskite Ba₂InOsO₆ using density functional theory (DFT). Our results show that the ferromagnetic phase is the most stable, with the net magnetic moment primarily arising from the Os atom. The half-metallic behavior exhibited by Ba₂InOsO_6, characterized by a band gap of 3.62 eV in the TB-mBJ + U approximation, decreases upon the inclusion of spin–orbit coupling (SOC). This half-metallic property, coupled with the stability of the ferromagnetic phase, makes Ba₂InOsO₆ particularly suitable for spintronic applications, as it can facilitate efficient spin injection and transport. Elasticity analysis indicates moderate brittleness, while thermoelectric properties, calculated using the Boltzmann transport model, reveal n-type conductivity and notable thermopower, suggesting potential for thermoelectric applications. This work provides a solid foundation for future experimental studies and potential applications in advanced technologies.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"611 ","pages":"Article 172629"},"PeriodicalIF":2.5,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142571696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Theory analysis and experimental study on magnetic fluid injection of multi-stage magnetic fluid seal","authors":"Jiawei Liu ,&nbsp;Decai Li ,&nbsp;Jiahao Dong ,&nbsp;Sijia Liu ,&nbsp;Jingcheng Cai","doi":"10.1016/j.jmmm.2024.172615","DOIUrl":"10.1016/j.jmmm.2024.172615","url":null,"abstract":"<div><div>Magnetic fluid seal (MFS) is one of the most mature applications of magnetic fluid (MF) and is widely used in numerous fields. But challenges arise in maintaining the volume of MF within the sealing gap, particularly under conditions of elevated seal pressure, high rotational speeds, and long-term usage. Injecting MF in multi-stage MFS post-installation poses a notable challenge. The conventional approach of injecting the entire optimal volume into pole teeth faces difficulties, as a portion of the MF tends to adhere to the surface of shaft and pole shoes during installation due to the uneven magnetic field. This study aimed to explore MF injection and devise a method for precisely controlling the MF volume in the sealing gap. To achieve this, a novel concept of multi-stage MFS with larger sealing gaps in specific stages was introduced. The injection and movement of MF were scrutinized through a combination of Computational Fluid Dynamics (CFD) simulations and experimental investigations. The findings from both CFD and experiments unequivocally establish the feasibility of injecting MF in multi-stage MFS. Effective injection is achieved when the inlet pressure increment is maintained below 20 kPa each time. Furthermore, experimental results highlight that the sealing capacity achieved through the injection method surpasses that of the common injection method, particularly for optimal volume MFS.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"611 ","pages":"Article 172615"},"PeriodicalIF":2.5,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142571695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical assessment of black powder removal from natural gas using magnetophoresis","authors":"Ali Mahmoudi,&nbsp;Majid Mesbah","doi":"10.1016/j.jmmm.2024.172616","DOIUrl":"10.1016/j.jmmm.2024.172616","url":null,"abstract":"<div><div>This paper addresses the persistent issue of black powder—solid suspended particles in natural gas streams—that can cause significant damage to gas industry equipment. Despite existing purification processes, black powder remains a challenge due to the limitations of conventional particle removal techniques. To overcome these drawbacks, this study proposes a novel magnetic filter that offers superior efficiency in capturing even submicron particles, significantly reducing maintenance costs and addressing the longstanding problem of black powder accumulation. The properties of black powder and existing separation methods in the natural gas industry are explored, and the performance of the magnetic filter is evaluated through comprehensive numerical analysis using the Discrete Phase Model (DPM). Results demonstrate the filter’s capability to efficiently capture particles as small as 5 µm, with an impressive removal efficiency of 92% for particles as small as 1 µm. This study provides valuable insights into addressing the persistent issue of black powder in natural gas streams and presents a promising solution for its efficient removal, ensuring the long-term integrity and durability of equipment used in natural gas transmission systems.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"611 ","pages":"Article 172616"},"PeriodicalIF":2.5,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142537484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Broadband microwave absorption and electromagnetic properties of Gd–Al–Co-doped M−type barium hexaferrite in 2–18 GHz range","authors":"Weihua Liao,&nbsp;Kai Huang,&nbsp;Wenwen Xu,&nbsp;Jiangying Yu,&nbsp;Ping Li,&nbsp;Jinrong Xu","doi":"10.1016/j.jmmm.2024.172609","DOIUrl":"10.1016/j.jmmm.2024.172609","url":null,"abstract":"<div><div>Gd–Al–Co-doped BaFe_12−3x(GdAlCo)_xO₁₉ (x = 0, 0.1, 0.2, 0.3, 0.4) was synthesized via the hydrothermal method. We performed comprehensive characterization using XRD, SEM, BET, VSM, XPS, and VNA techniques to explore the impact of substituting magnetic Co²⁺, Gd³⁺, and nonmagnetic Al³⁺ for Fe³⁺ on the morphology, specific surface area, magnetic, and microwave absorption (MWA) properties of BaFe_12−3x(GdAlCo)_xO₁₉. Investigating the MWA properties of BaFe_12−3x(GdAlCo)_xO₁₉ in the 2–18 GHz range, we find that all doped samples demonstrate excellent MWA characteristics. The sample BaFe_11.1(GdAlCo)_0.3O₁₉ achieves a minimum reflection loss (RL_min) of − 48.13 dB at a thickness of 2.07 mm, indicating an absorption of over 99 % of incident microwaves. The effective absorption bandwidth (EAB) for all four groups of doped samples exceeds 5.98 GHz. Notably, the x  = 0.1 samples reach an EAB of 9.15 GHz at only 2.0 mm thickness, covering most of the X-band and the entire Ku band. Gd-Al-Co co doping of BaFe₁₂O₁₉ not only improves its reflection loss ability, but also increases its absorption bandwidth. Improved the drawbacks of narrow bandwidth and poor loss capability in BaFe₁₂O₁₉. Consequently, BaFe_12−3x(GdAlCo)_xO₁₉ material shows significant potential for practical applications.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"612 ","pages":"Article 172609"},"PeriodicalIF":2.5,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Single-molecule Magnets (SMM) spin channels connecting FeMn antiferromagnet and NiFe ferromagnetic electrodes of a tunnel junction","authors":"Babu Ram Sankhi ,&nbsp;Erwan Peigney ,&nbsp;Hayden Brown ,&nbsp;Pius Suh ,&nbsp;Carlos Rojas-Dotti ,&nbsp;José Martínez-Lillo ,&nbsp;Pawan Tyagi","doi":"10.1016/j.jmmm.2024.172608","DOIUrl":"10.1016/j.jmmm.2024.172608","url":null,"abstract":"<div><div>The integration of single-molecule magnets (SMMs) into magnetic tunnel junctions (MTJs) offers significant potential for advancing molecular spintronics, particularly for next-generation memory devices, quantum computing, and energy storage technologies such as solar cells. In this study, we present the first demonstration of SMM-induced spin-dependent properties in an antiferromagnet-based MTJ molecular spintronic device (MTJMSD). We engineered cross-junction-shaped devices comprising FeMn/AlO_x/NiFe MTJs. The AlO_x barrier thickness where the exposed junction edges meet was comparable to the SMM length, facilitating the incorporation of SMM molecules as spin channels for spin-dependent transport. The SMM channels enabled long-range magnetic moment ordering around molecular junctions, which were precisely engineered via fabrication processes. The SMM, composed of a [Mn₆(μ₃-O)₂(H₂N-sao)₆(6-atha)₂(EtOH)₆] (H₂N-saoH = salicylamidoxime, 6-atha = 6-acetylthiohexanoate) complex, featured thioester groups at the ends that upon hydrolysis they form bonds with the magnetic electrodes. SMM-treated junctions demonstrated a significant current enhancement, reaching up to 7 μA at an input voltage of 60 mV. Furthermore, SMM-doped junctions exhibited current stabilization in the μA range at lower temperatures, whereas the bare electrodes showed current suppression to the picoampere range. Magnetization measurements conducted at 55 K and 300 K on pillar-shaped devices revealed a reduction in magnetic moment at low temperatures. Additionally, Kelvin probe atomic force microscopy (KPAFM) measurements confirmed that SMM integration transformed the electronic properties over long ranges.These findings are attributed to the spin channels formed between magnetic metal electrodes, which enhance spin polarization at each magnetic electrode. Our research highlights the potential of using antiferromagnetic materials, characterized by minimal stray fields and zero net magnetization, to transform MTJMSD devices.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"611 ","pages":"Article 172608"},"PeriodicalIF":2.5,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142537483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quasi-isothermal magnetocaloric effect in the DyAl2 alloy in magnetic field up to 14 T","authors":"A.S. Kuznetsov ,&nbsp;A.V. Mashirov ,&nbsp;I.I. Musabirov ,&nbsp;M.S. Anikin ,&nbsp;V.I. Mitsiuk ,&nbsp;Yu.S. Koshkid’ko ,&nbsp;J. Ćwik ,&nbsp;A.P. Kamantsev ,&nbsp;E.E. Kokorina ,&nbsp;K.A. Kolesov ,&nbsp;V.G. Shavrov","doi":"10.1016/j.jmmm.2024.172612","DOIUrl":"10.1016/j.jmmm.2024.172612","url":null,"abstract":"<div><div>Experimental and analytical studies were carried out on the magnetocaloric effect (MCE) in the rare-earth alloy of the Laves phase DyAl₂, which has the second-order magnetic phase transition (PT) in the region of cryogenic temperatures. The measurements are carried out using an extraction magnetic calorimeter with a Bitter electromagnet. A polycrystalline DyAl₂ sample was synthesized followed by heat treatment. X-ray diffraction and elemental chemical analyzes are provided. The magnetization of the sample was measured in magnetic fields up to 13.5<!--> <!-->T. Calculations of the entropy changes of the magnetic subsystem ΔS_mag are provided. Measurements of the MCEs ΔT − effect in adiabatic and ΔQ − effect in quasi-isothermal conditions were carried out. The MCE investigated by direct method in the temperature range of 15–110 K and magnetic field up to 14 T. It was found that the maximum of the adiabatic MCE in the region of the Curie temperature of the DyAl₂ alloy under adiabatic magnetization in a magnetic field of 14<!--> <!-->T is ΔT = 12.94<!--> <!-->K. The obtained values are well approximated by the <span><math><mrow><mi>Δ</mi><mi>T</mi><mo>∼</mo><mi>Δ</mi><msup><mrow><mi>H</mi></mrow><mrow><mn>2</mn><mo>/</mo><mn>3</mn></mrow></msup></mrow></math></span>, The maximum value of the quasi-isothermal MCE is ΔQ = 3.1<!--> <!-->kJ/kg. The value corresponds to the maximum of the entropy change of the magnetic subsystem ΔS_mag = 32.3<!--> <!-->J/(kg*K). The influence of thermal contact resistance (TCR) on the results of measuring the MCE under quasi-isothermal conditions is assessed.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"612 ","pages":"Article 172612"},"PeriodicalIF":2.5,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic circular dichroism of f-f electron transitions in Ho3+ and Nd3+ ions in antiferromagnetic crystal Ho0.75Nd0.25Fe3(BO3)4 in the region of spin-reorientation transition","authors":"A.V. Malakhovskii,&nbsp;V.V. Sokolov,&nbsp;A.L. Sukhachev,&nbsp;I.A. Gudim","doi":"10.1016/j.jmmm.2024.172613","DOIUrl":"10.1016/j.jmmm.2024.172613","url":null,"abstract":"<div><div>Absorption and magnetic circular dichroism (MCD) spectra have been studied in the region of ⁵<em>I</em>₈ → ⁵<em>F</em>₂, ⁵<em>S</em>₂, ⁵<em>F</em>₃, and ⁵<em>F</em>₅ absorption bands of the Ho³⁺ ion and in the region of ⁴<em>I</em>_9/2→⁴<em>G</em>_7/2, ²<em>K</em>_13/2, ⁴<em>S</em>_3/2, ⁴<em>F</em>_7/2, ⁴<em>F</em>_5/2 and ²<em>H</em>_9/2 absorption bands of the Nd³⁺ ion in an antiferromagnetic trigonal crystal Ho_0.75Nd_0.25Fe₃(BO₃)₄ in the temperature range from 5 to 90 K. A qualitative change in the shape of the MCD spectra of Ho³⁺ ion was revealed during the spin-reorientation transition at <em>T</em>_R = 6.9 К. Below <em>T_R</em>, in the easy-axis state of the crystal, the MCD spectrum has a shape typical for paramagnets, i.e., it consists of diamagnetic and paramagnetic parts. Just above <em>T</em>_R, in the easy-plane state of the crystal, MCD of Ho³⁺ ion has a spectrum similar to the absorption spectrum, which is typical for the paramagnetic part of the MCD. It was shown, that in the easy-plane state the exchange field of iron, being perpendicular to the external field directed along the <em>C</em>₃ axis, quenches the usual paramagnetic and diamagnetic MCD in Ho³⁺ ion, but creates a condition for the appearance of a large paramagnetic MCD of mixing (<em>B</em>-term). With temperature increasing, the MCD spectrum of Ho³⁺ ion gradually turns into a spectrum typical for paramagnets with the predominance of the sign-changing diamagnetic part, because the influence of the exchange field decreases. The shape of the MCD spectra of Nd³⁺ ions are typical for paramagnets but does not change during the reorientation transition in the rest of the crystal. This means that the magnetic moment of the Nd³⁺ ion does not make a reorientation transition simultaneously with the Fe³⁺ and Ho³⁺ ions of the rest of the crystal. This phenomenon is accounted for by a strong local magnetic anisotropy of the Nd³⁺ ion and by a weak exchange interaction Fe-Nd, which is not enough for rotation of the Nd³⁺ ion moment synchronously with that of the Fe³⁺ ion. The magneto-optical properties of neodymium are controlled by the easy-axis anisotropy of neodymium.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"611 ","pages":"Article 172613"},"PeriodicalIF":2.5,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142571660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}