Evidence for a Magnetic Seebeck Effect

The irreversible thermodynamics of a continuous medium with magnetic dipoles predicts that a temperature gradient in the presence of magnetization waves induces a magnetic induction field, which is the magnetic analog of the Seebeck effect. This thermal gradient modulates the precession and relaxation. The magnetic Seebeck effect implies that magnetization waves propagating in the direction of the temperature gradient and the external magnetic induction field are less attenuated, while magnetization waves propagating in the opposite direction are more attenuated.

Figure 1

Time-resolved transmission measurement of magnetization waves.

Figure 2

Propagation of magnetization waves from the cold to the hot side (top) and vice versa (bottom). The cones describe the precession of the magnetization at excitation $\mathbf{m}(0)$ and at detection $\mathbf{m}(\tau )$. The amount of damping depends on the relative orientation ${\mathbf{k}}_T$ of the temperature gradient with respect to the magnetization wave propagation direction $-{\mathbf{k}}^{-1}$.

Figure 3

Transmitted signals from the cold to the hot side and from the hot to the cold side as a function of the magnetic field ${\mathbf{B}}_0$ and of the detection time after a 15 ns pulsed excitation at 4.36 GHz. The lighter areas correspond to a larger signal.

Figure 4

Transmitted signal as a function of time after a 15 ns pulsed excitation at 4.36 GHz.

Figure 5

FMR signal of a 15 ns pulsed excitation at 4.36 GHz detected after 70 ns, after baseline correction.