Abstract: A thermoelectric material includes a parent phase in which an MgSiSn alloy is a main component, a void formed in the parent phase, and a silicon layer that is formed on at least a wall surface of the void and that includes silicon as a main component. The thermoelectric material further includes MgO in an amount of 1.0 wt. % or more and 20.0 wt. % or less. The silicon layer includes amorphous Si, or amorphous Si and nanosized Si crystals, and the parent phase includes a region in which the composition ratio of the Si of the chemical composition of the MgSiSn alloy is higher than in the other regions and a region in which the composition ratio of the Sn of the chemical composition of the MgSiSn alloy is higher than in the other regions. With these configurations, the thermoelectric material realizes both lower thermal conductivity and lower electrical resistivity.

Abstract: A thermoelectric material includes a parent phase in which an MgSiSn alloy is a main component, a void formed in the parent phase, and a silicon layer that is formed on at least a wall surface of the void and that includes silicon as a main component. The thermoelectric material further includes MgO in an amount of 1.0 wt. % or more and 20.0 wt. % or less. The silicon layer includes amorphous Si, or amorphous Si and nanosized Si crystals, and the parent phase includes a region in which the composition ratio of the Si of the chemical composition of the MgSiSn alloy is higher than in the other regions and a region in which the composition ratio of the Sn of the chemical composition of the MgSiSn alloy is higher than in the other regions. With these configurations, the thermoelectric material realizes both lower thermal conductivity and lower electrical resistivity.

Abstract: A piezoelectric actuator mechanism including: a screw-driven feeding mechanism that has a feed screw (11) and a feed screw nut (14); a disc-shaped rotor (17) mounted on the rear-end face of the feed screw nut (14); an ultrasonic motor (18) having a piezoelectric vibrator (19) that comes in contact with the circumference face of the rotor (17); and a driven mounting portion that is pressed against the leading end of the feed screw 11 by spring force, and displaced and positioned by the feeding operation of the feed screw. The driven mounting portion can be made to be a mirror holder (1) for use in an optical system, or a movable table (21) of a linear stage.