Photothermally modulated spatially resolved FMR detection of Walker modes in yttrium iron garnet spheres O. von Geisau, F. Rödelsperger, F. Schreiber, H. Benner and J. Pelzl J. Phys. IV France, 04 C7 (1994) C7-655-C7-658 DOI: 10.1051/jp4:19947155