Low Temperature Behaviour and Aging

8 Low Temperature Behaviour and Aging 5.8.1 Describing y(T) with Sheng s Formula 

If one tries to fit equ. 7 to the experimental y(T) data of oxygen aged samples, it is found that an almost perfect fit is still possible, though not in the whole temperature range between 0.4 K and 300 K as for freshly-prepared samples, but only between a temperature T qc where T qc loc/ decreases much 

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