Ultrasonic velocity and attenuation in kcl and KBr containing Li+∗

Ultrasonic Velocity and Attenuation in Alkali Halides Containing CN− II. Theoretical Interpretation

“…Although in the system under consideration quantum effects, e.g. tunneling, are of importance, the theory will still be valid, provided measurements are made at temperatures high enough to populate the tunnel states, and at frequencies much lower than the tunnel frequency [3].3) In this temperature and frequency region the compliance change 6s can be expected to be proportional to 1/T and independent of frequency.…”

An ESR Study of Li+ Impurity Ion Deformational Fields in KTaO3

“…This allows to make a conclusion about the strong "stretching" of local deformational distortion due to lithium ions in the direction of their off-centre displacement. Note that in KCl : Li the quadrupole part of the deformation tensor 9, = sZl, -8, is considerably smaller than its dilatational part 8, (correspondingly 0.16 eV and 5 eV [15]), so the ratio 811/82, z 1'). On the other hand, representing the elastic ' ) The dilatational part of the deformation tensor for KCl : Li in [15] was calculated theoretically, because it could not be measured by acoustic methods.…”

Structural phase transition induced by elastic fields of impurities

“…(1982). These authors estimated the quadrupole part of the elastic dipole R, 2: 1 eV, The R, value turned out to be one order of magnitude higher than in K , -,Li,CI (Byer and Sack, 1968), and so the elastic interaction in KTaO, is much stronger than in K , -,LixC1. But, as follows from the relation (6), it is necessary to know the value of the elastic dipole dilatational part R, in order to state that a ferroelastic phase transition takes place.…”