Sperl, Matthias and Singh, Avinash and Wurstbauer, Ursula and Das, Subrat Kumar and Sharma, Anand and Hirmer, Michael and Nolting, Wolfgang and Back, Christian H. and Wegscheider, Werner and Bayreuther, Guenther (2008) Spin-wave excitations and low-temperature magnetization in the dilute magnetic semiconductor (Ga,Mn)As. PHYSICAL REVIEW B, 77 (12): 125212. ISSN 1098-0121,
Full text not available from this repository. (Request a copy)Abstract
The spontaneous magnetization as a function of temperature has been investigated for a number of ( Ga, Mn ) As layers grown on GaAs ( 001 ) using superconduction quantum interference device magnetometry. The measurements have been performed with a focus on the low- temperature behavior of the magnetization. The temperature dependence of the spontaneous magnetization MS for T= 0.5T(C) is found to be well described by Bloch's T(3/2) law for all measured samples. However, we observe an extraordinary enhancement of the spin- wave parameter compared to conventional 3d ferromagnets such as Fe, which implies an enhanced low- temperature decay of the magnetic order. For a thorough understanding of this result, we have theoretically investigated the effect of dilution ( disorder ) on the finite- temperature spin dynamics and on the spin- wave parameter. It is shown that, due to the preferential accumulation of holes in spin clusters, which weakens the majority bulk spin coupling and results in low- energy magnon softening, there is a strong enhancement in the low- temperature decay of the magnetization with dilution. We find excellent agreement between the calculated and measured values for the spin- wave parameter.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | GA1-XMNXAS; FILMS; FERROMAGNETISM; RESONANCE; FIELD; GAAS; |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Chair Professor Back > Group Christian Back Physics > Institute of Experimental and Applied Physics > Alumni or Retired Professors > Group Werner Wegscheider |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 09 Nov 2020 08:49 |
| Last Modified: | 09 Nov 2020 08:49 |
| URI: | https://pred.uni-regensburg.de/id/eprint/31342 |
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