Observation of room temperature ferromagnetism and exchange bias in a 55Mn+ ion-implanted unintentionally doped [formula omitted]-[formula omitted] single crystal

Abstract

In this manuscript, the structural and magnetic properties of a 55Mn+ ion-implanted unintentionally doped β-Ga2O3 single crystal are investigated. The implanted Mn+ ions cause crystalline degeneration due to the formation of defects in the surface of the substrate. Room temperature ferromagnetism (FM) is observed in the samples with implantation doses of 5 × 1014cm-2, 1 × 1015cm-2 and 5 × 1015cm-2. The zero-field-cooled (ZFC)/field-cooled (FC) measurement of magnetization reveals that the ion implantation process induces an antiferromagnetic (AFM) phase. The temperature evolution of the remanence asymmetry (ME) demonstrates the typical behavior of the exchange bias effect due to the coexistence of FM and AFM phases. Based on the distribution of Mn+ ions and defects and the relationship between the remanence asymmetry (ME) and the exchange bias field (HE), the single domain and core-shell models are used to investigate the exchange bias system. The formation mechanism of the ferromagnetic order is briefly discussed, which is rather different from the one corresponding to the bound magnetic polaron (BMP) model.