Nauka i Obrazovanie (Jan 2015)
Surface Magnetostatic Waves in Films of the Cubic Ferrites Oriented Along the Crystallographic Planes of Symmetry
Abstract
The aim of the work is to study characteristics of magneto-static waves in the tangently magnetized films with crystallographic orientations of 100 and 110 types. Properties of the symmetry of planes allow us to set orientation of magnetization vector of only one angular variable because both this vector and a magnetizing field will be located in the film plane. This circumstance significantly simplifies calculations. Dispersion laws of magneto-static waves are derived, and temperature coefficients of frequencies are calculated on their basis. Angular dependences of obtained expressions are analyzed. The special attention is given to the orientations of the magnetization vector coinciding with directions of the tangential crystallographic axes of 100 , 110 , 111 types. These directions are characterized by extreme frequency values and their temperature coefficients. The paper studies conditions under which there is a zero value in the angular dependence of the frequency temperature coefficient. The investigation concerned the analysis of a sign of the temperature coefficient for 100 and 110 directions in a film with 100 orientation and for 100 and 111 directions in a film with 110 orientation. The sign inverse conditions lead to the inequalities making a connection between the film magnetic parameters themselves. The paper analyses conditions of thermo-stabilizing frequencies of a surface magneto-static wave spectrum in the yttrium iron garnet film. It is found that in 100 and 110 orientation films such conditions can be satisfied in the long-wave part of a spectrum. In this case a temperature coefficient is positive for the axis of 100 type and negative for the axes of 110 and 111 types. For comparison, the 111 orientation films possess weak anisotropy of the surface wave characteristics. In such films a temperature coefficient is negative for all tangent directions. The paper gives results of experimentally investigated yttrium iron garnet films with orientation of 100 type. It shows that frequencies of a surface wave in these films can be thermo-stabilized. The work results can be used to improve characteristics of film materials and increase thermal stability of spin wave devices.
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