Signatures of Unconventional Magnetism in the Layered Metallic Ferromagnet LaCrSb 3 From Ferromagnetic Resonance Spectroscopy

ABSTRACT is a metallic ferromagnet with a layered crystal structure demonstrating intriguing electronic and magnetic properties, such as large anomalous Hall effect, strong canting of the spin lattice, and a peculiar spin‐reorientation transition. Here, we report the results of the temperature‐dependent X‐ray diffraction, static magnetization, and in particular electron spin resonance (ESR) and ferromagnetic resonance (FMR) experiments carried out over a wide range of frequencies, magnetic fields, and temperatures. Though X‐ray data reveals no structural transition down to 15 K, a strong magneto‐elastic coupling is detected across the ferromagnetic transition at K. ESR results indicate a presence of the quasi‐static short‐range correlations extending far above , which is a typical fingerprint of the low‐dimensional magnetism. The frequency‐field diagram of the FMR modes mapped below strongly suggests presence of two magnetic sublattices in . A quantitative understanding of the FMR excitations was achieved within a phenomenological model of interacting orthogonal ferro‐ and antiferromagnetic sublattices, which was earlier proposed to explain unusually strong spin canting observed by neutron diffraction [E. Granado et al., Phys. Rev.Lett. 89 , 107204 (2002)]. The FMR results corroborate this scenario and call for the development of the underlying microscopic model of unconventional magnetism in .