Electron spin resonance inEuB6

Abstract

Cavity measurements of a high frequency ͑60 GHz͒ electron spin resonance ͑ESR͒ have been carried our for a single crystal of EuB 6 at temperatures 4.2-50 K in magnetic field up to 7 T, which has been aligned along ͓001͔ crystallographic direction. It is found that in the case of homogeneous magnetic field in the sample the ESR spectrum of EuB 6 is formed by a single line at all temperatures including the ferromagnetic ordering region, whereas the gradient of magnetic field in the samples induces double peak ESR structure at low temperatures. For the quantitative description of the ESR line shape we suggested an analytical approach applicable for the cavity measurements of a metal with an arbitrary value of magnetic permeability including strongly magnetic case and obtained full set of the ESR parameters, namely oscillating magnetization M 0 , g factor, and linewidth. Our analysis has explained the visible resonance line shift and revealed the coincidence of the oscillating magnetization defining the resonance amplitude with the static magnetization. The anomalous growth of the linewidth below Curie temperature T C Ϸ 15 K is observed. We argue that ESR in EuB 6 is not considerably affected by either interaction with the spin polarons or the magnetic phase separation and reflects merely the oscillation of the Eu 2+ localized magnetic moments, which can be well understood within meanfield approximation.

Magnetic resonance anisotropy in CeB6: an entangled state of the art

“…It is visible that theoretical analysis may adequately reproduce experimental data. Similar fits were performed for all the temperatures studied and were used to obtain temperature dependences for the g -factors g(T ), line widths W(T ) and oscillating magnetization M 0 ( T ) as described in refs 7,15,16. The results are presented in Fig.…”

“…The ESR data processing schema71516 allowed obtaining resonant magnetoabsorption spectra in the units of magnetic permeability μ R . As a general rule, the ESR line broadens when the temperature is approaching to the P-AFQ phase boundary (Fig.…”

“…The ESR technique used includes special geometry of cavity measurements allowing the absolute calibration of microwave absorption by the metallic sample in units of magnetic permeability71516. In this geometry, the cavity bottom is made of thin copper foil with a small hole at the maximum of microwave magnetic field.…”

“…In this paper, we aim to fill this gap intending to make a detailed inspection of the predictions of the theoretical model suggested in refs 13 and 14. An original experimental technique of cavity measurements, which allows finding the full set of ESR spectroscopic parameters including the oscillating magnetization, line width and g -factor in the case of strongly correlated metals71516 is applied. This investigation may shed more light on the nature of unusual static and dynamic magnetic properties of CeB 6 , which still remain the subject of debates in spite of more than a forty years old history of studies of this amazing material.…”

Angular Dependences of ESR Parameters in Antiferroquadrupolar Phase of CeB6

“…Magnetic resonance experiments were carried out with the use of homemade spectrometer based on Agilent E8361C Network Analyzer at temperature T = 1.8 K. The method based on the comparative analysis of resonator magnetoabsorption and magnetoresistive ρ(H) dependences was applied to obtain ESR curves in units of magnetic permeability [8]. …”