Ettingshausen effect

The Etingshausen effect is the effect of the appearance of a temperature gradient in a conductor located in a magnetic field through which an electric current flows. If current flows along the axis $x$ ${\ displaystyle x}$ $x$ and the magnetic field is directed along $y$ ${\ displaystyle y}$ $y$ then a temperature gradient will occur along $z$ ${\ displaystyle z}$ $z$ . The effect is named after Albert von Ettinshausen .

A brief explanation of the effect is as follows. On average, the action of the Lorentz force and the Hall field cancel each other, however, due to the dispersion of the velocities of the charge carriers , the deviation of the “hotter” and “colder” occurs in different ways - they deviate to opposite sides of the conductor.

When electrons collide with a lattice , they come into thermodynamic equilibrium with it. If they give energy, the conductor heats up; if they absorb lattice energy, then the conductor cools, resulting in a temperature gradient in the direction perpendicular to the field $B$ ${\ displaystyle B}$ $B$ and current $j$ ${\ displaystyle j}$ $j$ .

The characteristic of this effect is the Ettingshausen coefficient $A^{E}$ ${\ displaystyle A ^ {E}}$ ${\ displaystyle A ^ {E}}$ :

\nabla _{z}T^{E}=A^{E}B_{y}j_{x}

{\ displaystyle \ nabla _ {z} T ^ {E} = A ^ {E} B_ {y} j_ {x}}

{\ displaystyle \ nabla _ {z} T ^ {E} = A ^ {E} B_ {y} j_ {x}}

.

The Ettingshausen effect can only be adiabatic.

Since the Hall field depends on the velocity of charge carriers, the effect in semiconductors is stronger by several orders of magnitude than in metals.

The effect is significant when, instead of the Hall field, the Lorentz force in an alternating magnetic field is used (there is very little information).

Literature

Physical Encyclopedic Dictionary. / Ch. ed. A.M. Prokhorov. Ed. count D.M. Alekseev, A.M. Bonch-Bruevich, A.S. Borovik-Romanov, etc. - M.: Sov. Encyclopedia, 1984. - 944 p., ill., 2 l. silt

Ettingshausen effect

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Literature

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