Room‐temperature ferromagnetism in Cr‐doped GaN films grown by MOMBE on GaAs(111)A substrates

Abstract

PACS 75.50. Pp, 81.05.Ea, 81.15.Hi c-axis-oriented Cr-doped hexagonal GaN films with Cr of 0.3, 1 and 5 at.% were epitaxially grown on GaAs(111)A substrates by metal organic molecular beam epitaxy (MOMBE) with metal Ga and dimethylhydrazine (DMHy) as a nitrogen source. Clear hysteresis loop was observed in magnetization versus magnetic filed (M -H) curves for Cr-doped GaN films, and the ferromagnetic behaviour was confirmed even at 350 K. The saturation magnetization per Cr atom is estimated to be approximately 1 Bohr magnetron at 300 K.

Electronic Structure Characteristics of MBE (molecular beam epitaxy)-Grown Diluted Magnetic Semiconductor Ga1-xCrxN Films

“…4,5) Recent experimental results of transition metal doped GaN and GaAs thin films grown by the molecular beam epitaxy (MBE) method indeed confirm ferromagnetic T C 's over room temperature. [6][7][8][9][10] These high T C DMS materials are candidates for 'spintronics' devices. 11,12) The electronic structure changes upon substitution of transition metal ions in the host lattice is of direct importance in knowing the mechanism of ferromagnetism.…”

Room‐temperature ferromagnetism in V‐doped GaN thin films grown by MOCVD

“…Though, XRD measurements showed the absence of impurity phases as V clusters, V-Ga alloys or V-N compounds, but we do not exclude the possibility of the presence of V, V-Ga or V-N nanoscale precipitates, which cannot be measured by XRD for its insensitivity on nanoscale [17,18]. Ternary phases (GaCrN) have been observed for Cr-doped GaN by Suemasu et al [19].…”

Cr concentration dependence of magnetic and electrical properties of Cr‐doped GaN films on Si (111) by MOMBE

“…There have been a lot of works on Cr-doped GaN, and several groups have already reported RT ferromagnetism in Cr-doped GaN, which was confirmed by a superconducting quantum interference device (SQUID) [6,7]. We have also reported RT ferromagnetism in Cr-doped GaN films grown by metal organic molecular beam epitaxy (MOMBE) [8]. However, the origin of the observed ferromagnetism is still under discussion.…”