小晶粒核壳结构LaNiMnO中的自旋向上转换、交换相互作用及定制磁性能

Spin-up conversion, exchange-interactions, and tailored magnetic properties in core-shell LaNiMnOof small crystallites.

作者信息

Hissariya R, Babu S, Ram S, Mishra S K

机构信息

School of Materials Science and Technology, Indian Institute of Technology (BHU), Varanasi- 221 005, India.

Materials Science Centre, Indian Institute of Technology, Kharagpur-721 302, India.

出版信息

Nanotechnology. 2021 Aug 2;32(43). doi: 10.1088/1361-6528/ac13eb.

DOI:10.1088/1361-6528/ac13eb

PMID:34256367

Abstract

LaNiMnO-a ferromagnetic (FM) insulator offers tunable charge carriers and spins useful to devise its multiple properties and applications. In this view, we studied a core-shell LaNiMnO(2-3 nm shell on 65 - 80 nm core) of a Ni/Ni(d) to Mn/Mn(d) spin-up conversion- revived a new FM phase-2, raising a spin-density = 0.7 s aover the NiMnspecies (phase-1), = 0.5 s a, i.e. 2.12/f.u. larger spin moment. HRTEM images studied with x-ray diffraction characterizing core-shell structure that plays a crucial role in tuning the high spin FM phase-2 of profound properties. Below 110 K, the dc magnetization and ac magnetic susceptibility(,) reveal a metastable magnetic behavior on an antiferromagnetic canting of a spin-glass nature. The results follow a Vogel-Fulcher type relaxation with a relaxation time∼ 10s, confirming a spin-glass freezing behavior. Uniquely, FM field of phase-1 controls magnetics of phase 2 of a coupled magnet, modulating joint features with small thermal magnetic hysteresis on heating-cooling cycles.

摘要

LaNiMnO——一种铁磁（FM）绝缘体，提供了可调节的电荷载流子和自旋，有助于设计其多种特性和应用。基于此观点，我们研究了一种核壳结构的LaNiMnO（65 - 80纳米的核上有2 - 3纳米的壳），其从Ni/Ni（d）到Mn/Mn（d）的自旋向上转换恢复了一个新的FM相2，在NiMn物种（相1）上产生了自旋密度 = 0.7 s a，而相1的自旋密度为 = 0.5 s a，即每个化学式单位的自旋矩大2.12。通过X射线衍射研究的高分辨透射电子显微镜（HRTEM）图像表征了核壳结构，该结构在调节具有深刻特性的高自旋FM相2中起着关键作用。在110 K以下，直流磁化强度和交流磁化率（χ）揭示了自旋玻璃性质的反铁磁倾斜上的亚稳磁行为。结果遵循具有弛豫时间约为10 s的Vogel-Fulcher型弛豫，证实了自旋玻璃冻结行为。独特的是，相1的FM场控制着耦合磁体中相2的磁性，在加热-冷却循环中以小的热磁滞调制联合特征。