Pandey Abhishek, Mazumdar Chandan, Ranganathan R
S N Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata-700098, India. Experimental Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata-700064, India.
J Phys Condens Matter. 2009 May 27;21(21):216002. doi: 10.1088/0953-8984/21/21/216002. Epub 2009 Apr 24.
We report the change in the valency of Eu-ions in the binary intermetallic cubic compound EuPd(3) induced by La doping at rare-earth sites. Doping of La generates negative chemical pressure in the lattice, resulting in a significant increase of the lattice parameter without altering the simple-cubic structure of the compound. Results of dc-magnetic measurements suggest that this increase in the lattice parameter is associated with the valence transition of Eu-ions from Eu(3+) to a mixed-valent state. As Eu(2+)-ions possess a large magnetic moment, this valence transition significantly modifies the magnetic behavior of the compound. In contrast to introducing boron at the vacant body center site of the unit cell to change the valency of Eu-ions, as in the case of EuPd(3)B, our results suggest it can also be altered by doping a rare-earth ion of larger size at the lattice site of Eu in EuPd(3).
我们报道了在二元金属间立方化合物EuPd₃中，通过在稀土位点进行La掺杂所引起的Eu离子价态变化。La的掺杂在晶格中产生负化学压力，导致晶格参数显著增加，而不改变该化合物的简单立方结构。直流磁测量结果表明，晶格参数的这种增加与Eu离子从Eu³⁺到混合价态的价态转变有关。由于Eu²⁺离子具有较大的磁矩，这种价态转变显著改变了该化合物的磁行为。与在EuPd₃B的情况中，在晶胞的空体心位置引入硼来改变Eu离子的价态不同，我们的结果表明，在EuPd₃中，通过在Eu的晶格位置掺杂更大尺寸的稀土离子，也可以改变Eu离子的价态。
