Accession Number : AD0655085

Title :   MAGNETOELASTIC PROPERTIES OF YIG AS A FUNCTION OF TEMPERATURE,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE MICROWAVE AND QUANTUM MAGNETICS GROUP

Personal Author(s) : Platzker,Aryeh

Report Date : JAN 1967

Pagination or Media Count : 56

Abstract : The temperature dependence of first order magnetoelastic constants (b sub 1, b sub 2) and second order elastic constants (c sub 11, c sub 12, c sub 44) of yttrium iron garnet is obtained from sound velocity measurements in the range 80-300k. The group velocity of selected magnetoelastic modes in single crystals is measured by an ultrasonic system at a frequency of 30MHz as a function of applied magnetic field and temperature. The elastic constants are found to increase monotonically by a small amount upon decreasing the temperature. A 3% change from the room temperature value is observed at 80k. The temperature dependence of the magnetoelastic constants as reported here is in good agreement with previously published values that were obtained by static (length changes vs. magnetic field) methods. For b sub 1 the values of 3,240,000 erg/cc at 296k and 2,200,000 erg/cc at 80k are obtained. For b sub 2 the values 7,260,000 erg/cc and 12,600,000 erg/cc respectively are obtained. The coupled mechanical-magnetic equations of motion are decoupled and a 3 x 3 matrix is found. The corresponding eigenvalues give the dispersion relations of a magnetoelastic wave propagation at an arbitrary direction with respect to the magnetic field and the crystal coordinates. (Author)

Descriptors :   (*FERROMAGNETIC MATERIALS, MAGNETOSTRICTION), YTTRIUM COMPOUNDS, IRON COMPOUNDS, GARNET, TEMPERATURE, ELASTIC PROPERTIES, EQUATIONS OF MOTION, MECHANICAL WAVES, PROPAGATION, STRAIN(MECHANICS), MAGNETIC FIELDS, INTERACTIONS

Subject Categories : Miscellaneous Materials
      Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE