Abstract
The pseudo-binary phase diagram between NdBa_2Cu_3O_x and Ba_3Cu_<10>O_<13>, and the crystallization of NdBa_2Cu_4O_x in air have been observed in-situ using high temperature optical microscopy. For Ba_3Cu_<10>O_<13> composition range of 0-60mol%, the crystallization of NdBa_2Cu_3O_x via the peritectic reaction (Nd_4Ba_2Cu_2O_<10> +L→NdBa_2Cu_4O_x) has been directly ob. served. On the other hand, for higher flux composition the growth mechanism of NdBa_2Cu_4O_x changed from polyhedral via stacked to dendritic crystals with increasing cooling rate.