“…The study of magnon-phonon interactions in highquality magnets has a long history [14][15][16][17][18][19][20][21]. The arrival of crystal growth techniques, strongly improved microwave technology, and discovery of new phenomena such as the spin Seebeck effect, led to a revival of the subject in the past few years, with emphasis on ultrathin films and heterostructures [4,6,[22][23][24][25][26][27][28][29][30].…”