Publisher Summary This chapter focuses on magneto-optical properties of alloys and intermetallic compounds; and discusses some general aspects relating to magneto-optical effects, microscopic models based on intraband and interband transitions, the experimental results obtained on the ferromagnetic 3d metals (Ni, Co and Fe), intermetallic compounds, and the results obtained on ternary compounds. As most of the magneto-optic measurements are made at room temperature, the binary compounds considered have to be magnetically ordered at room temperature. In the ternary compounds each of the three atomic species occupies a different crystallographic site. Representatives of this class of materials are the well-known Heusler alloys. Considerable effort has gone into the study of magneto-optical properties of thin films of amorphous alloys formed by combining rare earth metals with 3d metals. The magneto-optical effects can be studied either in transmission (Faraday effect) or in reflection (Kerr effect). For metallic systems magneto-optical studies made by means of the Kerr effect have a certain number of advantages relative to studies by means of the Faraday effect.

Chapter 5 Magneto-optical properties of alloys and intermetallic compounds

The time changes in the amplitude dependent internal friction are studied in β-tin crystals, 99.99% pure, and oriented for the [001] slip. The measurements are made during the free decay of transverse vibration. Comparison of the results with the theory of Granato and Lucke leads to the following conclusions: (a) The length of movable dislocation increases as the amplitude of excitation is increased. (b) The length also increases with the duration of excitation at constant driving force, as log (γ t +1). This is considered to be due to breakaway from the atmosphere of solute atoms. After the breakaway, the diffusion of solute atoms from the atmosphere of the movable dislocation takes place, around room temperature. At low temperatures, the diffusion does not take place, but the brokenaway dislocation moves large distances in the lattice. The amplitude dependent internal friction is in this case caused by the interaction of the movable dislocation with the solute atoms distributed in the lattice.

Time Dependent Internal Friction in Tin Crystals

Physikalische Eigenschaften der festen Salze

A recovery with time of the amplitude of an ultrasonic third harmonic wave in single crystal NaCl after applying a static deforming stress has been investigated. The recovery is found to be temperature dependent with an activation energy of 0·32 ev. Simultaneous measurements of the attenuation of the fundamental wave revealed a similar recovery for which an activation energy has also been measured. A recovery of the third harmonic amplitude has also been observed following the eventual removal of the deforming stress. The kinetics of the recovery of the third harmonic amplitude and also of the fundamental wave attenuation are found to obey a t⅓ ageing law.

Recovery of ultrasonic third harmonic amplitude changes in sodium chloride following small plastic deformation

The Hysteresis Phenomena of Internal Friction Measurements in NaCl Crystals

Time-Dependent Internal Friction in Deformed NaCl Crystals

Granato-Lucke Plot Derived from the Time-Dependent Internal Friction Measurements

Time-dependent properties of the strain amplitude dependent internal friction in alkali halide crystals were systematically investigated. The measurement technique more reliable than the conventional one was established, and repeatable enhancement and recovery of the internal friction due to external excitation was discovered. A new procedure for the Granato-Lucke plot was derived from recovery of the internal friction. At the same time, this procedure itself shows validity of the Granato-Lucke theory. The enhancement and recovery was interpreted in terms of the diffusion process of pinning elements during breakaway and the counter-diffusion process of pinning elements during resting of the dislocation-motion. The nature of hysteresis phenomena in internal friction measurements in NaCl crystals was also interpreted by the same mechanism.

Hiroo Natsume

Papers

Time-Dependent Internal Friction in Deformed NaCl Crystals

The Hysteresis Phenomena of Internal Friction Measurements in NaCl Crystals

Granato-Lucke Plot Derived from the Time-Dependent Internal Friction Measurements

Time-Dependent Internal Friction in Deformed Alkali Halide Crystals