Parametric Magneto‐Acoustic Resonance in CaBiV Garnet

For cubic monocrystalline Bi 0,5Ca2.5Feg., 5V1.25012 garnets Manzel and Linzen (1) have found the existence of two peaks of the imaginary part of the microwave susceptibility f( h, H, w1 ) for subsidiary ferrimagnetic resonance by parallel pumping with linear polarized microwaves of an amplitude h > h in orientation of applied dc field H parallel to [I00 J at room temperature. h denotes thethreshold value for parametric excitation of magnons, and w1 is the fixed pump frequency.In this letter we will give some results which show that a possible explanation of these two peaks at characterized dc fields called H the linear anisotropic interaction (2, 3) between parametrically excited magnons and lattice phonons with longitudinal (1) and transversal (t) polarization, respectively. In respectof this conception we have calculated the contribution of xu for an isolated 2-magnon-1-phonon confluence process where two parametrically excited and energetically degenerate acoustical magnons with wave vectors a,, a2, frequencies w( 5 ) = w( 'b2) = wl/2, and polar angles e% = 0% = ~/ 2 with respect to [ 1001 as polar axis confluence due to linear magnetoelastic interaction into a nonthermal or thermal acoustical phonon with wave vector g, frequency w (q, a), and polarization s = 1, t . This dynamical relaxation process is nonlinear because both the number and the damping of magnons depend on the microwave power, and conservation of energy fio(al) + Ru, (a,) = %hw (q, 8) and of momentum %g1 + hS2 = hq are demanded. Applying the technique of nonequilibriumGreen's functions (4) we obtain for the nonlinear steady-state response at H C

mentioning

confidence: 99%

Nonlinear Two‐Magnon‐One‐Phonon Confluence Process in BVC Garnet

Haubenreißer

1968

“…V 0 (CaBiVIG) with high Curie temperature and relatively low Ca2xBi3-2xFe5-x x 1 2 saturation magnetization attracts more and more attention. It is of great interest to investigate the magneto-elastic properties of this material (1,2).…”

mentioning

confidence: 99%

Magneto‐Elastic Coupling Coefficients of Ca‐Bi‐V‐I‐Garnet

Mandel

Smokotin

Petrakovskiı̌

et al. 1968

Self Cite

Excitation of Magnetostatic, Magnetoelastic, and Acoustic Waves in CaBiVFe Garnet

Mironov

Shevlyagin

Gurevich

et al. 1968

The excitation of traveling magnetostatic, magnetoelmtic, and acoustic waves by means of rf magnetic field was observed previously in Y-Fe garnet PIG) (l).We present here experimental results on excitation of such waves in single-crystalline Ca-Bi-V-Fe garnet. This substance has nearly the same linewidth (2) as YIG. But its saturation magnetization (2) and the effective magnetoelastic interaction constant (3) are coneiderably less than those reported for YIG.The specimen used was a rod (1 = 0.6 cm, d = 0.18 cm) with the axis nearly parallel to the [110] dirwtion and optically flat end faces. The specimen was placed in a uniform external d\: magnetic field Ho parallel to its axis. Thin wire' antenna provided r f magnetic field perpendicular to Ho. The experiments were performed at mom temperature in the frequency band 300 to 2000 MHz with power input in the milliwatt range. Standard pulse echo technique was used; the experimental apparatus has been descrmed elsewhere (1). Short microwave pulses ( ul ps) were applied to one end of the sample, and echoes were observed at the opposite end. Oscilloscope traces typical of propagation of various modes are shown in Fig. 1. The first echo transit time 71 and the insertion loss N1 are plottad in Fig. 2 as a function of Ho.width of this pulse is larger than the input pulse width because of the strong disAt low values of Ho the magnetostatic echo pulse is observed (Fig. la). The persion. The delay time T~ of this echo increased rapidly with the increase of €Io from nearly zero up to 7.5 pa. The observed 'tlm0) dependence shown in Fig. 2 6 physica