A. M. Kasumov, A. I. Dmitriev, V. V. Netyaga, K. A. Korotkov, V. M. Karavayeva, A. I. Ievtushenko
{"title":"f-d 相互作用对岛式 Fe/Gd2O3 纳米结构中隧道磁阻和磁阻的影响","authors":"A. M. Kasumov, A. I. Dmitriev, V. V. Netyaga, K. A. Korotkov, V. M. Karavayeva, A. I. Ievtushenko","doi":"10.1007/s11106-024-00436-2","DOIUrl":null,"url":null,"abstract":"<p>The potential for amplifying tunnel magnetoresistance and magnetoimpedance in island nanofilms without energy consumption or the use of amplifying devices was studied. Such amplification was observed for the films deposited on a Gd<sub>2</sub>O<sub>3</sub> layer instead of a glass substrate. The enhancement is due to the <i>f–d</i> exchange interaction established between atoms with unfilled <i>f</i>- and <i>d</i>-electron shells, present in both Fe and Gd<sub>2</sub>O<sub>3</sub>. The <i>f–d</i> exchange interaction enhances the ordering of the magnetic structure within the Fe ferromagnetic layer, increases its magnetization, and subsequently improves the properties that depend on this magnetization. Iron and Gd<sub>2</sub>O<sub>3</sub> were selected because the magnetic moments of Fe in the iron group and Gd in the lanthanide series are among the highest effective ones: μ<sub>Fe</sub> = 7.13 μ<sub>B</sub> and μ<sub>Gd</sub> = 7.95 μ<sub>B</sub>. This, according to theory, determines the high energy of the <i>f–d</i> exchange interaction. The island morphology of Fe films deposited on a Gd<sub>2</sub>O<sub>3</sub> layer enabled electron tunneling under the influence of the <i>f–d</i> exchange interaction. This allowed the study of tunnel magnetoresistance under direct current and magnetoimpedance under alternating current influenced by the <i>f–d</i> exchange interaction. The frequency dependence of the active component <i>Z'</i>, the reactive component <i>Z''</i>, and the total impedance <i>Z</i> of Fe films on glass and Gd<sub>2</sub>O<sub>3</sub> substrates, without and under a constant magnetic field of 7500 Oe, was analyzed. These characteristics are used to determine the frequency dependence of tunnel magnetoimpedance and estimate tunnel magnetoresistance for Fe island films on glass and Gd<sub>2</sub>O<sub>3</sub> substrates. These characteristics were found to be 55 % higher, on average, for Fe deposited on Gd<sub>2</sub>O<sub>3</sub> than for Fe on glass, both at a low frequency of 0.1 Hz for tunnel magnetoresistance and at higher frequencies of 1–10<sup>5</sup> Hz for tunnel magnetoimpedance. This results from the influence of <i>f–d</i> exchange interaction on electron tunneling between the iron islands.</p>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"63 1-2","pages":"30 - 36"},"PeriodicalIF":0.9000,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Influence of f–d Interaction on Tunnel Magnetoresistance and Magnetoimpedance in Island Fe/Gd2O3 Nanostructures\",\"authors\":\"A. M. Kasumov, A. I. Dmitriev, V. V. Netyaga, K. A. Korotkov, V. M. Karavayeva, A. I. Ievtushenko\",\"doi\":\"10.1007/s11106-024-00436-2\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>The potential for amplifying tunnel magnetoresistance and magnetoimpedance in island nanofilms without energy consumption or the use of amplifying devices was studied. Such amplification was observed for the films deposited on a Gd<sub>2</sub>O<sub>3</sub> layer instead of a glass substrate. The enhancement is due to the <i>f–d</i> exchange interaction established between atoms with unfilled <i>f</i>- and <i>d</i>-electron shells, present in both Fe and Gd<sub>2</sub>O<sub>3</sub>. The <i>f–d</i> exchange interaction enhances the ordering of the magnetic structure within the Fe ferromagnetic layer, increases its magnetization, and subsequently improves the properties that depend on this magnetization. Iron and Gd<sub>2</sub>O<sub>3</sub> were selected because the magnetic moments of Fe in the iron group and Gd in the lanthanide series are among the highest effective ones: μ<sub>Fe</sub> = 7.13 μ<sub>B</sub> and μ<sub>Gd</sub> = 7.95 μ<sub>B</sub>. This, according to theory, determines the high energy of the <i>f–d</i> exchange interaction. The island morphology of Fe films deposited on a Gd<sub>2</sub>O<sub>3</sub> layer enabled electron tunneling under the influence of the <i>f–d</i> exchange interaction. This allowed the study of tunnel magnetoresistance under direct current and magnetoimpedance under alternating current influenced by the <i>f–d</i> exchange interaction. The frequency dependence of the active component <i>Z'</i>, the reactive component <i>Z''</i>, and the total impedance <i>Z</i> of Fe films on glass and Gd<sub>2</sub>O<sub>3</sub> substrates, without and under a constant magnetic field of 7500 Oe, was analyzed. These characteristics are used to determine the frequency dependence of tunnel magnetoimpedance and estimate tunnel magnetoresistance for Fe island films on glass and Gd<sub>2</sub>O<sub>3</sub> substrates. These characteristics were found to be 55 % higher, on average, for Fe deposited on Gd<sub>2</sub>O<sub>3</sub> than for Fe on glass, both at a low frequency of 0.1 Hz for tunnel magnetoresistance and at higher frequencies of 1–10<sup>5</sup> Hz for tunnel magnetoimpedance. This results from the influence of <i>f–d</i> exchange interaction on electron tunneling between the iron islands.</p>\",\"PeriodicalId\":742,\"journal\":{\"name\":\"Powder Metallurgy and Metal Ceramics\",\"volume\":\"63 1-2\",\"pages\":\"30 - 36\"},\"PeriodicalIF\":0.9000,\"publicationDate\":\"2024-10-22\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Powder Metallurgy and Metal Ceramics\",\"FirstCategoryId\":\"88\",\"ListUrlMain\":\"https://link.springer.com/article/10.1007/s11106-024-00436-2\",\"RegionNum\":4,\"RegionCategory\":\"材料科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"MATERIALS SCIENCE, CERAMICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Powder Metallurgy and Metal Ceramics","FirstCategoryId":"88","ListUrlMain":"https://link.springer.com/article/10.1007/s11106-024-00436-2","RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATERIALS SCIENCE, CERAMICS","Score":null,"Total":0}
Influence of f–d Interaction on Tunnel Magnetoresistance and Magnetoimpedance in Island Fe/Gd2O3 Nanostructures
The potential for amplifying tunnel magnetoresistance and magnetoimpedance in island nanofilms without energy consumption or the use of amplifying devices was studied. Such amplification was observed for the films deposited on a Gd2O3 layer instead of a glass substrate. The enhancement is due to the f–d exchange interaction established between atoms with unfilled f- and d-electron shells, present in both Fe and Gd2O3. The f–d exchange interaction enhances the ordering of the magnetic structure within the Fe ferromagnetic layer, increases its magnetization, and subsequently improves the properties that depend on this magnetization. Iron and Gd2O3 were selected because the magnetic moments of Fe in the iron group and Gd in the lanthanide series are among the highest effective ones: μFe = 7.13 μB and μGd = 7.95 μB. This, according to theory, determines the high energy of the f–d exchange interaction. The island morphology of Fe films deposited on a Gd2O3 layer enabled electron tunneling under the influence of the f–d exchange interaction. This allowed the study of tunnel magnetoresistance under direct current and magnetoimpedance under alternating current influenced by the f–d exchange interaction. The frequency dependence of the active component Z', the reactive component Z'', and the total impedance Z of Fe films on glass and Gd2O3 substrates, without and under a constant magnetic field of 7500 Oe, was analyzed. These characteristics are used to determine the frequency dependence of tunnel magnetoimpedance and estimate tunnel magnetoresistance for Fe island films on glass and Gd2O3 substrates. These characteristics were found to be 55 % higher, on average, for Fe deposited on Gd2O3 than for Fe on glass, both at a low frequency of 0.1 Hz for tunnel magnetoresistance and at higher frequencies of 1–105 Hz for tunnel magnetoimpedance. This results from the influence of f–d exchange interaction on electron tunneling between the iron islands.
期刊介绍：
Powder Metallurgy and Metal Ceramics covers topics of the theory, manufacturing technology, and properties of powder; technology of forming processes; the technology of sintering, heat treatment, and thermo-chemical treatment; properties of sintered materials; and testing methods.
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