High-Field ESR

The combination of terahertz spectroscopy with magnetic fields opens the possibilities to investigate electron spin resonance at high frequencies. In the simplest case the spectra can be obtained as field-scans of the transmittance at fixed frequency. In addition, the frequency spectra at fixed field can be measured. This is especially useful in some antiferromagnets with weak field-dependence of the resonance frequency. In some special cases, e.g. to separate magnetic and electric contributions, the phase shift of the signal is measured.

Antiferromagnetic resonances in La0.95Sr0.05MnO3
Magnetic field-dependence of the resonance frequencies of the AFMR lines in La0.95Sr0.05MnO3 at low temperatures. These results provide experimental evidence for the canted magnetic structure in low-doped LSMO and they cannot be explained on the basis of the phase-separation scenario.
Ferromagnetic resonances in metallic ferromagnet
High-field ESR spectra of La0.825Sr0.175MnO3 in the reflectance geometry. The ferromagnetic resonance (FMR) and antiresonance (FMAR) modes are marked by arrows. Symbols - experiment, lines - fit. The line splitting of the FMR mode is due to the anisotropy of the crystal field below the rhombohedral-to-orthorhombic phase transition at TRO. The inset shows the temperature dependence of the resonance-line positions [Ref.].

Selected publications

  • M. V. Eremin, D. V. Zakharov, H.-A. Krug von Nidda, R. M. Eremina, A. Shuvaev, A. Pimenov,  P. Ghigna, J. Deisenhofer, and A. Loidl
    Dynamical Dzyaloshinsky-Moriya Interaction in KCuF3
    Phys. Rev. Lett. 101, 147601 (2008)
  • J. Deisenhofer, R. M. Eremina, A. Pimenov, T. Gavrilova, H. Berger, M. Johnsson, P. Lemmens, H.-A. Krug von Nidda, A. Loidl, K.-S. Lee, M.-H. Whangbo
    Structural and magnetic dimers in the spin-gapped system CuTe2O5
    Phys. Rev. B 74, 174421 (2006)
  • A. A. Mukhin, A. Pimenov, M. Biberacher, and A. Loidl
    Antiferromagnetic resonances and magnetization of a canted  antiferromagnet
    J. Magn. Res. 170, 8 (2004)
  • D. Ivannikov, M. Biberacher, H.-A. Krug von Nidda, A. Pimenov, A. Loidl, A. A. Mukhin, and A. M. Balbashov
    High-field ESR spectroscopy of the spin dynamics in La1-xSrxMnO3 (x <= 0.175)
    Phys. Rev. B 65, 214422 (2002)
  • A. Pimenov, M. Biberacher, D. Ivannikov, A. Loidl, V. Yu. Ivanov, A. A. Mukhin, and A. M. Balbashov
    High-Field AFMR and magnetization of La0.95Sr0.05MnO3 single crystal: Evidence for the existence of the canted magnetic structure
    Phys. Rev. B 62, 5685 (2000)
  • A. A. Mukhin, V. Yu. Ivanov, V. D. Travkin, A. Pimenov A. Loidl and A. M. Balbashov
    Antiferromagnetic Resonance in the Canted Phase of La1-XSrXMnO3: Experimental Evidence Against Electronic Phase Separation
    Europhys. Lett. 49, 514 (2000)