Magnetovolume Effect and Negative Thermal Expansion in Mn3(Cu1 xGex)N
نویسندگان
چکیده
Metallic manganese nitrides Mn3AN (A 1⁄4 Zn, Ga, etc) are well-known for their large magnetovolume effect (MVE), i.e., a discontinuous volume expansion at the magnetic transition. However, MVE is exceptionally absent in Mn3CuN. We found that MVE is recovered by a small amount of Ge in the Cu site. This revival seems to coincide with recovery of the cubic structure. By further Ge doping, the volume expansion becomes gradual ( T 100K) and large negative thermal expansion (NTE) is exhibited around room temperature [ 1⁄4 12 10 6 K 1 ( : coefficient of linear thermal expansion) for Mn3(Cu0:5Ge0:5)N]. Such a large, isotropic and non-hysteretic NTE is desirable for practical applications.
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