@article{732b540ffc0a4e2c85782f5089cbe2a1,
title = "Single and multidomain characteristics of GaMnAs investigated by magnetotransport measurements",
abstract = "We have investigated the magnetization reorientation process of GaMnAs ferromagnetic films by changing external field direction in planar Hall effect (PHE) measurement. While the angular dependences of PHE data taken with clockwise and counterclockwise under strong magnetic field (i.e., above 400 Oe) are completely overlapped without hysteresis, they are significantly different under small magnetic field (i.e., below 50 Oe) by exhibiting nonabrupt hysteresis. We have analyzed such angular dependence of PHE using the magnetic free energy based on Stoner-Wohlfarth model. The behavior observed under the high field was well understood in terms of coherent rotation of magnetization in the form of single domain. However, the nonabrupt hysteric behavior observed with low field cannot be explained by a single domain picture and requires involvement of multidomain structures.",
author = "Jungtaek Kim and Shin, {D. Y.} and Taehee Yoo and Hyungchan Kim and Sanghoon Lee and X. Liu and Furdyna, {J. K.}",
note = "Funding Information: This work was supported by Korea Research Foundation Grant No. KRF-2004-005-C00068, by a Korea University Grant, by the Seoul R&DB Program, and by the National Science Foundation Grant No. DMR06-03762. FIG. 1. Angular dependence of planar Hall resistance data taken at 13 K . The magnetic field direction was rotated within (001) plane at several different magnetic fields. The open and solid circles represent data points taken from clockwise and counterclockwise scans at the same field strength, respectively. FIG. 2. Plot of the relation between φ M and φ H mapped out from PHR data shown in the top panel. The solid line is the result of the best fitting obtained using the magnetic free energy model. FIG. 3. Energy diagram as a function of magnetization direction. The diagram was obtained at a fixed magnetic field direction of φ H = 125 ° . It is clear that the number of minima marked as arrows decreases as field strength increases. FIG. 4. (a) Angular dependence of planar Hall resistance data taken at fixed field strength of H = 30 Oe by changing the magnetic field direction. (b) and (c) show the calculated area portion p of the magnetic domain for the transition regions marked A and B, the magnetization across the [110] and the [ 1 ¯ 10 ] crystallographic directions, respectively. ",
year = "2008",
doi = "10.1063/1.2828532",
language = "English",
volume = "103",
journal = "Journal of Applied Physics",
issn = "0021-8979",
publisher = "American Institute of Physics Publising LLC",
number = "7",
}