ESR in quasi 2-d ferromagnets: The coexistence of paramagnetic excitations and magnetostatic spin waves and new interference effects

The quasi 2-dimensional layer structures (CnH2n+1NH3)2CuCl4 with n = 1,2 have been investigated by electron spin resonance. New phenomena arise for samples with well defined natural surfaces: (i) well resolved magnetostatic volume and surface spin wave modes at 4.2 K comparable in quality with spectra of YIG, (ii) a magnetostatic spin wave spectrum which is coincident with the paramagnetic resonance over a wide temperature range, (iii) interference effects between these two types of resonances. © 1975.