Field-induced spin reorientation in Eu[sub 2]CuO[sub 4]:Gd studied by magnetic resonance

Journal Article · Wed Dec 01 04:00:00 EST 1993 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.48.16775· OSTI ID:5773705

Fainstein, A; Butera, A; Zysler, R D; Tovar, M ^[1]; Rettori, C; Rao, D; Oseroff, S B ^[2]; Fisk, Z ^[3]; Cheong, S ^[4]; Vier, D C; Schultz, S ^[5]

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1. Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica, 8400 San Carlos de Bariloche, Rio Negro (Argentina)
2. San Diego State University, San Diego, California 92182 (United States)
3. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
4. AT T Bell Laboratories, Murray Hill, New Jersey 07974 (United States)
5. University of California San Diego, San Diego, California 92037 (United States)

We report a magnetic-resonance study of Gd-doped Eu[sub 2]CuO[sub 4] single crystals. Cooling the samples in a magnetic field [bold H][sub FC], induces weak ferromagnetism (WF), with a strong out-of-plane anisotropy determined by the Dzyaloshinsky-Moriya (DM) interaction. In addition, there is in-plane anisotropy with an easy-axis parallel to the [110] crystal axis closest to [bold H][sub FC]. An intense resonance mode is observed at the [ital X] band (9.5 GHz) when [bold H][sub FC] is applied parallel to one of the [l angle]110[r angle] axes and the measuring field is rotated by 90[degree] in the CuO[sub 2] plane. At the [ital Q] band (35 GHz), the in-plane resonance modes strongly depend on angle and temperature. We analyze the experimental results in terms of a phenomenological model for the magnetic free energy, which predicts a reorientation transition of the WF component of the magnetization [bold m][sub WF] induced by the external field. Associated with this transition, a softening of the WF magnetic resonance mode occurs when the external field is applied perpendicular to the easy magnetization axis. The resulting angular variation of the resonance modes depends on whether the energy gap for the magnetic excitations is larger or smaller than the microwave energy. From the resonance data we have determined both the out-of-plane and in-plane anisotropy fields, [ital H][sub DM]([ital T]) and [ital H][sub ax]([ital T]), respectively.

• OSTI ID: 5773705
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 48:22; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360606* -- Other Materials-- Physical Properties-- (1992-)
ALLOYS
ANISOTROPY
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTALS
EUROPIUM COMPOUNDS
EUROPIUM OXIDES
GADOLINIUM ADDITIONS
GADOLINIUM ALLOYS
MAGNETIC RESONANCE
MICROWAVE SPECTRA
MONOCRYSTALS
ORIENTATION
OXIDES
OXYGEN COMPOUNDS
RARE EARTH ADDITIONS
RARE EARTH ALLOYS
RARE EARTH COMPOUNDS
RESONANCE
SPECTRA
SPIN ORIENTATION
TEMPERATURE RANGE
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TRANSITION ELEMENT COMPOUNDS