SrAgZn and EuAgZn with KHg2-type structure-Structure, magnetic properties, and 151Eu Mossbauer spectroscopy

Samples of SrAgZn and EuAgZn were synthesized by reaction of the elements in sealed tantalum crucibles. Both structures were refined on the basis of single crystal X-ray diffractometer data: KHg2-type, Imma, a=476.7(1), 6=780.9(2), c=810.1(2) pm, R-1/wR(2)=0.0189/0.0119, 381 F-2 values for SrAg1.12Zn0.88 and a=474.43(9), b=760.8(2), c=799.0(2) pm, R-1/wR(2)=0.0226/0.0483, 370 F-2 values for EuAg1.17Zn0.83 with 13 variables per refinement. Silver and zinc are randomly distributed on the Hg position and build up three-dimensional networks. EuAgZn shows ferromagnetic ordering at 29(1) K. In the temperature range from 75 to 300 K the sample shows Curie Weiss behaviour with mu(eff)=7.87(1) 1.43/Eu atom and theta(P)=37.1(1) K, indicating divalent europium. 151Eu Mossbauer spectroscopic measurements confirmed the divalent state with an isomer shift of -9.31 mm/s at 78 K. Temperature dependent mu(B)/Eu data show first magnetic hyperfine field splitting at 25 K and a saturated magnetization of 17 T at 5.2 K. The temperature dependence can be described by an S=7/2 Brillouin function. (C) 2013 Elsevier Inc. All rights reserved.