Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200241, People's Republic of China.
Phys Rev Lett. 2013 Sep 6;111(10):107203. doi: 10.1103/PhysRevLett.111.107203. Epub 2013 Sep 4.
Reversibly switching interlayer exchange coupling (IEC) of magnetic semiconductor multilayers between ferromagnetic (FM) and antiferromagnetic (AFM) modes is a difficult but key issue for fabricating semiconductor giant magnetoresistance devices. Here, we show that such tunable IEC is achievable around room temperature in Co-doped TiO2/VO2 diluted magnetic semiconductor multilayers. On the basis of first-principles calculations of electronic structure and fermiology, it is clarified that, associated with the metal-insulator transition (MIT) of nanosized VO2 spacers, exotic short-range magnetic orders are developed in the multilayers so that the IEC can be tuned reversibly from FM mode to AFM mode by varying temperature crossing the MIT (∼340 K).
在室温下实现钴掺杂 TiO2/VO2 稀磁半导体多层膜中层间交换耦合（IEC）从铁磁（FM）到反铁磁（AFM）模式的可逆转换是制造半导体巨磁电阻器件的一个难题，但也是一个关键问题。本文表明，通过第一性原理计算电子结构和费米子理论，在纳米尺寸 VO2 间隔层的金属-绝缘体转变（MIT）的基础上，多层膜中会产生奇异的短程磁有序，从而使 IEC 能够通过跨越 MIT（约 340 K）的温度变化，从 FM 模式可逆地调至 AFM 模式。
