{"title":"Crystal and thermodynamic properties of Tb2Ni2X, (X = Al, Ga)","authors":"","doi":"10.1016/j.physb.2024.416525","DOIUrl":null,"url":null,"abstract":"<div><p>The crystal and thermodynamic properties of <span><math><mrow><msub><mrow><mtext>Tb</mtext></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mtext>Ni</mtext></mrow><mrow><mn>2</mn></mrow></msub><mtext>X</mtext></mrow></math></span> (X = Al, Ga) are reported through measurements of X-ray diffraction (XRD), magnetic susceptibility, <span><math><mrow><mi>χ</mi><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span>, magnetization, <span><math><mrow><mi>M</mi><mrow><mo>(</mo><msub><mrow><mi>μ</mi></mrow><mrow><mn>0</mn></mrow></msub><mi>H</mi><mo>)</mo></mrow></mrow></math></span> and heat capacity, <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mi>p</mi></mrow></msub><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span>. XRD pattern analysis confirms the orthorhombic <span><math><mrow><msub><mrow><mtext>W</mtext></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mtext>CoB</mtext></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span>-type structure with the space group of <span><math><mrow><mi>I</mi><mi>m</mi><mi>m</mi><mi>m</mi></mrow></math></span>. <span><math><mrow><mi>χ</mi><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> at high temperature for both compounds follows the Curie – Weiss relationship giving an effective magnetic moment close to that expected for the trivalent Tb ion. The low-temperature <span><math><mrow><mi>χ</mi><mrow><mo>(</mo><msub><mrow><mi>C</mi></mrow><mrow><mi>p</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> data indicate that both compounds order antiferromagnetically at <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub></math></span> = 41 K (40.4 K) and 41.5 K (41.4 K) for Al and Ga compounds, respectively. <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mi>p</mi></mrow></msub><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> data of the nonmagnetic counterparts <span><math><mrow><msub><mrow><mtext>Y</mtext></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mtext>Ni</mtext></mrow><mrow><mn>2</mn></mrow></msub><mtext>X</mtext></mrow></math></span> (X = Al, Ga) are well described by the Debye model giving a Debye temperature, <span><math><msub><mrow><mi>θ</mi></mrow><mrow><mi>D</mi></mrow></msub></math></span> = 236.9(4) K and 225.3(2) K for Al and Ga compounds, respectively. The low-temperature part of the <span><math><mrow><mn>4</mn><mi>f</mi></mrow></math></span>-magnetic contribution to the total heat capacity, <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>4</mn><mi>f</mi></mrow></msub><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> can be described by the antiferromagnetic spin-wave dispersion, giving an energy gap <span><math><msub><mrow><mi>Δ</mi></mrow><mrow><mi>s</mi><mi>w</mi></mrow></msub></math></span> = 47(3) K and 26(2) K for Al and Ga compounds, respectively. The <span><math><mrow><mn>4</mn><mi>f</mi></mrow></math></span> – magnetic entropy <span><math><mrow><msub><mrow><mi>S</mi></mrow><mrow><mn>4</mn><mi>f</mi></mrow></msub><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> for both compounds reaches the value of <span><math><mrow><mn>2</mn><mi>R</mi><mi>l</mi><mi>n</mi><mrow><mo>(</mo><mn>2</mn><mo>)</mo></mrow></mrow></math></span> close to their respective <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub></math></span> values.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8000,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physica B-condensed Matter","FirstCategoryId":"101","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0921452624008664","RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"PHYSICS, CONDENSED MATTER","Score":null,"Total":0}
引用次数: 0
Abstract
The crystal and thermodynamic properties of (X = Al, Ga) are reported through measurements of X-ray diffraction (XRD), magnetic susceptibility, , magnetization, and heat capacity, . XRD pattern analysis confirms the orthorhombic -type structure with the space group of . at high temperature for both compounds follows the Curie – Weiss relationship giving an effective magnetic moment close to that expected for the trivalent Tb ion. The low-temperature data indicate that both compounds order antiferromagnetically at = 41 K (40.4 K) and 41.5 K (41.4 K) for Al and Ga compounds, respectively. data of the nonmagnetic counterparts (X = Al, Ga) are well described by the Debye model giving a Debye temperature, = 236.9(4) K and 225.3(2) K for Al and Ga compounds, respectively. The low-temperature part of the -magnetic contribution to the total heat capacity, can be described by the antiferromagnetic spin-wave dispersion, giving an energy gap = 47(3) K and 26(2) K for Al and Ga compounds, respectively. The – magnetic entropy for both compounds reaches the value of close to their respective values.
期刊介绍:
Physica B: Condensed Matter comprises all condensed matter and material physics that involve theoretical, computational and experimental work.
Papers should contain further developments and a proper discussion on the physics of experimental or theoretical results in one of the following areas:
-Magnetism
-Materials physics
-Nanostructures and nanomaterials
-Optics and optical materials
-Quantum materials
-Semiconductors
-Strongly correlated systems
-Superconductivity
-Surfaces and interfaces