XPS Study of Mechanically Activated YBa₂Cu₃O_6+δ and NdBa₂Cu₃O_6+δ

Table 1

Phase composition, lattice parameters, and the size of coherent scattering regions (𝐿) for YBa₂Cu₃O_6+δ and NdBa₂Cu₃O_6+δ before and after mechanical treatment.

Crystallographic parameters	Milling duration in AGO-2
(1)  YBa2Cu3O6+𝛿 powders
	0 s; (sample Y-0)	30 s; (sample Y-0.5)	2 min; (sample Y-2)	10 min; (sample Y-10)
The main phase—orthorhombic S.G. Pmmm
𝑎,Å	3.8208(3)	3.8218(3)	3.8287(10)	3.8344(10)
𝑏,Å	3.8884(5)	3.8893(5)	3.8938(15)	3.8879(15)
𝑐,Å	11.6809(11)	11.6793(12)	11.6739(33)	11.6663(31)
𝑉,Å^3	173.541(53)	173.599(55)	174.036(161)	173.919(158)
Impurity, mass%	—	~5%  Y2BaCuO5	~5%  Y2BaCuO5	~7%  Y2BaCuO5
𝐿, nm	167	57	25	20
(2)  NdBa2Cu3O6+𝛿 powders
	0 s; (sample N-0)	30 s; (sample N-0.5)	2 min; (sample N-2)	10 min; (sample N-10)
The main phase—orthorhombic S.G. Pmmm
𝑎,Å	3.8677(1)	3.8731(3)	3.8727(12)	3.8754(12)
𝑏,Å	3.9202(1)	3.9206(10)	3.9225(14)	3.9161(15)
𝑐,Å	11.7612(3)	11.7622(24)	11.7630(39)	11.7661(24)
𝑉,Å^3	178.328(6)	178.608(118)	178.688(178)	178.564(212)
Impurity, mass%	~3%  Ba2Cu3O5+𝑥	—	—	—
𝐿, HM	179.2	32.5	22.9	16.9