MATERIALS LETTERS
LI L, XU Y, YANG F, LI JJ, TAO JH, CAI X, XU K, WANG JF, CAO B
JOURNAL OF PHYSICS DAPPLIED PHYSICS
RAN JX, HE R, WANG LL, LIU BZ, JI XL, SUN JY, WANG JX, LI JM, WEI TB