Understanding and controlling complex states arising from magnetic frustration

Zapf, Vivien¹ 

[1] Los Alamos National Laboratory

关键词: AMPLIFICATION;    ANTIFERROMAGNETISM;    CRYSTAL STRUCTURE;    ELECTRONS;    FERROMAGNETISM;    MAGNETIC FIELDS;    MAGNETISM;    NATIONAL SECURITY;    SENSITIVITY;    SPIN;   

DOI  :  10.2172/1042994
RP-ID  :  LA-UR-12-21829
PID  :  OSTI ID: 1042994
Others  :  TRN: US1203071

学科分类：凝聚态物理

美国|英语

来源: SciTech Connect

【 摘 要 】

Much of our national security relies on capabilities made possible by magnetism, in particular the ability to compute and store huge bodies of information as well as to move things and sense the world. Most of these technologies exploit ferromagnetism, i.e. the global parallel alignment of magnetic spins as seen in a bar magnet. Recent advances in computing technologies, such as spintronics and MRAM, take advantage of antiferromagnetism where the magnetic spins alternate from one to the next. In certain crystal structures, however, the spins take on even more complex arrangements. These are often created by frustration, where the interactions between spins cannot be satisfied locally or globally within the material resulting in complex and often non-coplanar spin textures. Frustration also leads to the close proximity of many different magnetic states, which can be selected by small perturbations in parameters like magnetic fields, temperature and pressure. It is this tunability that makes frustrated systems fundamentally interesting and highly desirable for applications. We move beyond frustration in insulators to itinerant systems where the interaction between mobile electrons and the non-coplanar magnetic states lead to quantum magneto-electric amplification. Here a small external field is amplified by many orders of magnitude by non-coplanar frustrated states. This greatly enhances their sensitivity and opens broader fields for applications. Our objective is to pioneer a new direction for condensed matter science at the Laboratory as well as for international community by discovering, understanding and controlling states that emerge from the coupling of itinerant charges to frustrated spin textures.