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AM: Magnetismus
AM 9: Poster: Magnetowid. (1-17), Dü. Schichten (18-34), Oberfl
ächenmag. (35,36), Mikr. Methoden (37-45), Mikromag. (46-58), Phasenüberg. (59-77), Spektroskop. (78-91), Nanokr.Mat.(92-96), Anisotrop. (97-101), Schmelzen(102-104),Sonst/postdeadl.(105-109)
AM 9.97: Poster
Dienstag, 27. März 2001, 14:45–19:00, Foyer S 3
Ferromagnetic resonance and SQUID measurements on Fe-GaAs-heterostructures — •D. Spoddig1, R. Meckenstock1, J. Koch1, W. Keune2, M. Marysko3, Z. Frait3, and J. Pelzl1 — 1Inst. f. Exp.Physik, Ruhr-Universität-Bochum, 44780 Bochum, FRG — 2Lab. f. ang. Physik, Gerhard Mercator Universität, 47048 Duisburg, FRG — 3Inst. of Physics, ASCR, 182 21 Prague 8, CZ
Thin epitaxial (001)Fe-films were grown on (001) GaAs with a high electron mobility transistor (HEMT) structure. The samples were investigated by conventional angle dependent ferromagnetic resonance (FMR) at frequencies from 9 GHz to 69 GHz, by locally resolved photothermally modulated (PM-) FMR in x-band and SQUID-measurements at room-temperature. FMR results gave a ratio of 2 to 1 between crystalline and a uniaxial in plane anisotropy and small intrinsic line width. This ratio suggests additional steps in SQUID measurements, which could be observed at room-temperature. Frequency dependent FMR measurements show the theoretically expected linear behavior between linewidths and frequency. In addition PM-FMR provides besides the locally resolved FMR spectra a field independent background signal to the microwave response capable of characterizing the semiconductor. This is due to photo carriers excited in the GaAs by the laser light. Supported by DFG/SFB 491/EC Project HPRN-CT-1999-00150.