Temperature dependence of spin-polarization in FIS graphene junction

IF 2.5 3区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Magnetism and Magnetic Materials Pub Date : 2025-02-17 DOI:10.1016/j.jmmm.2025.172870

Hamidreza Emamipour

{"title":"Temperature dependence of spin-polarization in FIS graphene junction","authors":"Hamidreza Emamipour","doi":"10.1016/j.jmmm.2025.172870","DOIUrl":null,"url":null,"abstract":"<div><div>We study the effect of temperature on spin polarization in graphene-based ferromagnet insulator superconductor (FIS) junctions, theoretically. Within the framework of BTK (Blonder Tinkham Klapwijk) theory we find that when <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>F</mi></mrow></msub></math></span> is selected near to <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>x</mi></mrow></msub></math></span> (where <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>F</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>x</mi></mrow></msub></math></span> represent Fermi energy and exchange field in the ferromagnet region) and temperature approaches to <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> spin-polarization gets 100%. This case implies the spin-polarization is generated by just one spin species i.e. spin-up current, (<span><math><msub><mrow><mi>I</mi></mrow><mrow><mi>u</mi></mrow></msub></math></span>). We also obtain a phase diagram <span><math><mrow><msub><mrow><mi>E</mi></mrow><mrow><mi>x</mi></mrow></msub><mo>−</mo><mi>T</mi></mrow></math></span> which distinguishes SAR (specular Andreev reflection) from NAR (normal Andreev reflection). Therefore, the proposed junction may be applied not only to create huge spin-polarization which is significant in spintronic-industry but also to discriminate SAR and NAR from each other which is important in fundamental condensed matter physics.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"618 ","pages":"Article 172870"},"PeriodicalIF":2.5000,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Magnetism and Magnetic Materials","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0304885325001015","RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}

引用次数: 0

Abstract

We study the effect of temperature on spin polarization in graphene-based ferromagnet insulator superconductor (FIS) junctions, theoretically. Within the framework of BTK (Blonder Tinkham Klapwijk) theory we find that when

E_{F}

is selected near to

E_{x}

(where

E_{F}

and

E_{x}

represent Fermi energy and exchange field in the ferromagnet region) and temperature approaches to

T_{c}

spin-polarization gets 100%. This case implies the spin-polarization is generated by just one spin species i.e. spin-up current, (

I_{u}

). We also obtain a phase diagram

E_{x} - T

which distinguishes SAR (specular Andreev reflection) from NAR (normal Andreev reflection). Therefore, the proposed junction may be applied not only to create huge spin-polarization which is significant in spintronic-industry but also to discriminate SAR and NAR from each other which is important in fundamental condensed matter physics.

查看原文本刊更多论文

求助全文

约1分钟内获得全文求助全文

来源期刊

Journal of Magnetism and Magnetic Materials 物理-材料科学：综合

CiteScore

5.30

自引率

11.10%

发文量

1149

审稿时长

59 days

期刊介绍： The Journal of Magnetism and Magnetic Materials provides an important forum for the disclosure and discussion of original contributions covering the whole spectrum of topics, from basic magnetism to the technology and applications of magnetic materials. The journal encourages greater interaction between the basic and applied sub-disciplines of magnetism with comprehensive review articles, in addition to full-length contributions. In addition, other categories of contributions are welcome, including Critical Focused issues, Current Perspectives and Outreach to the General Public. Main Categories: Full-length articles: Technically original research documents that report results of value to the communities that comprise the journal audience. The link between chemical, structural and microstructural properties on the one hand and magnetic properties on the other hand are encouraged. In addition to general topics covering all areas of magnetism and magnetic materials, the full-length articles also include three sub-sections, focusing on Nanomagnetism, Spintronics and Applications. The sub-section on Nanomagnetism contains articles on magnetic nanoparticles, nanowires, thin films, 2D materials and other nanoscale magnetic materials and their applications. The sub-section on Spintronics contains articles on magnetoresistance, magnetoimpedance, magneto-optical phenomena, Micro-Electro-Mechanical Systems (MEMS), and other topics related to spin current control and magneto-transport phenomena. The sub-section on Applications display papers that focus on applications of magnetic materials. The applications need to show a connection to magnetism. Review articles: Review articles organize, clarify, and summarize existing major works in the areas covered by the Journal and provide comprehensive citations to the full spectrum of relevant literature.