Large Exchange Bias Triggered by Transition Zone of Spin Glass. Issue 3 (25th November 2022)

• Record Type: Journal Article
• Authors: Liao, Xiaoqi; Wei, Songrui; Wang, Yu; Wang, Dingchen; Wu, Kewen; Liang, Huawei; Yang, Sen; Svedlindh, Peter; Zeng, Yu‐Jia
• Is Part Of: ADVANCED PHYSICS RESEARCH. Volume 2:Issue 3(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-11-25
• Subjects: exchange bias -- machine learning -- magnetic shape memory alloys -- Monte Claro simulation -- spin glass; 530
• DOI: 10.1002/apxr.202200043
• Languages: English
• ISSNs: 2751-1200

Abstract

Abstract: Exchange bias has increasingly practical significance in magnetoresistive and spintronic devices. However, the underlying mechanism of exchange bias in bulk compounds with the structural single‐phase and inhomogeneous magnetic phases is still elusive. Herein, based on experimental and simulation results, two important parameters are studied, i.e., the antiferromagnetic (AFM) volume fraction and the ferromagnetic (FM)/AFM interface area, which essentially determine the (spontaneous) exchange bias of Mn‐rich Ni44 Co6 Mn44‐ x Sn6+ x ( x = 0 ∼ 6) magnetic shape memory alloys. The substitution Sn for Mn changes magnetic ground state following the sequence of superparamagnetic/AFM → dilute spin glass/AFM → transition zone → cluster spin glass/AFM → FM, accompanying the growth of FM cluster and the weakening of AFM interactions. The results reveal that the magnetic ground state for exchange bias is optimized at transition zone between dilute spin glass/strong AFM and cluster spin glass/weak AFM, in which the optimal AFM volume fraction and FM/AFM interface area are achieved by tuning magnetic fields. A giant exchange bias field of 702.7 mT and a spontaneous exchange bias field of 318.7 mT are demonstrated. The work contributes to in‐depth understanding of (spontaneous) exchange bias in magnetically inhomogeneous compounds. Abstract : Exchange bias has been investigated in Ni44 Co6 Mn44‐ x Sn6 +x alloys. This work reveals that the AFM volume fraction and the FM/AFM interface area essentially determine (spontaneous) exchange bias of Mn‐rich Ni44 Co6 Mn44‐ x Sn6+ x ( x = 0 ∼ 6) magnetic shape memory alloys, which can be optimized by tuning the magnetic ground state (composition x ) and magnetic field.