Hyperfine Interact DOI 10.1007/s10751-014-1112-x Hyperfine field at Mn in the intermetallic compound LaMnSi 2 measured by PAC using 111 Cd nuclear probe C. Domienikan · B. Bosch-Santos · G. A. Cabrera Pasca · R. N. Saxena · A. W. Carbonari © Springer International Publishing Switzerland 2014 Abstract Magnetic hyperfine field at Mn site has been measured in the orthorhombic inter- metallic compound LaMnSi 2 with PAC spectroscopy using radioactive 111 In- 111 Cd nuclear probe. Samples of LaMnSi 2 were prepared by melting pure metallic components in stoi- chiometric proportion in an arc furnace under argon atmosphere. The samples were sealed in a quartz tube under helium atmosphere, annealed at 1000 ◦ C for 60 h and quenched in water. Samples were analyzed with X-ray diffraction method. 111 In was introduced in the samples by thermal diffusion at 1000 ◦ C for 60 h. PAC measurements were carried out with a six BaF 2 detector spectrometer at several temperatures between 50 K and 410 K. Results show well defined quadrupole and magnetic interactions at all temperatures. The magnetic hyperfine field (B hf ) measured at 50 K is 7.1(1) T. The temperature dependence of B hf fol- lows the normal Brillouin-like behavior expected for a simple ferromagnetic ordering. The ferromagnetic transition temperature (T c ) was determined to be 401(1) K. Keywords Intermetallic compounds · Hyperfine field · Perturbed γ -γ angular correlation 1 Introduction Intermetallic compounds of the series RMnSi 2 , where R is a rare-earth element, crystallize in an orthorhombic TbFeSi 2 -type structure belonging to space group Cmcm. This structure can be described as built from the alternating (010) planes containing R, Mn and Si atoms in a sequence R-Si-Mn-Si-R-Si-Si-R-Mn-Si... atomic planes. This structure is closely related Proceedings of the 5th Joint International Conference on Hyperfine Interactions and International Symposium on Nuclear Quadrupole Interactions (HFI/NQI 2014) Canberra, Australia, 21–26 September 2014 C. Domienikan · B. Bosch-Santos · G. A. Cabrera Pasca · R. N. Saxena · A. W. Carbonari () Instituto de Pesquisas Energ´ eticas e Nucleares, Av. Prof. Lineu Prestes, 2242 – Cidade Universit´ aria – CEP 05508-000 S˜ ao Paulo, Brazil e-mail: carbonar@ipen.br