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Abstract: We present study of the anisotropic magnetocaloric effect in TbNiAl crystallizing in the hexagonal ZrNiAl-type structure. TbNiAl orders antiferromagnetically below T N =47K and undergoes second magnetic phase transition to another antiferromagnetic structure at T 1 =23K. Magnetization and specific heat measurements on single crystal revealed strongly anisotropic magnetocaloric effect. The large effect occurs for field applied along the hexagonal c-axis whereas the entropy change is almost zero for the perpendicular field direction. Plateau-like character of the determined temperature change is observed between T N and T 1. [Copyright &y& Elsevier]

Abstract: We present study of the anisotropic magnetocaloric effect in DyNiAl. This compound crystallizes in the hexagonal ZrNiAl-type structure, orders magnetically below and undergoes a further magnetic phase transition at . The Dy-moments are aligned ferromagnetically along the hexagonal -axis below , the additional antiferromagnetic component develops within the basal plane below . The magnetocaloric effect was evaluated from the magnetization measurements with field applied along the -axis and perpendicular to it. Our data reveal a strong anisotropy of the magnetocaloric effect. The large effect occurs for field applied along the -axis whereas the entropy change is small for the perpendicular field direction. [Copyright &y& Elsevier]

Abstract: We present the specific-heat study of the electronic properties of NpIrSn and NpNiSn, crystallizing in the ZrNiAl-type hexagonal and TiNiSi-type orthorhombic structure, respectively. NpIrSn orders antiferromagnetically below K and undergoes a further magnetic phase transition at K. The -coefficient of the electronic specific heat is only moderately enhanced to 75mJmol−1 K−2. ThIrSn, crystallizing in the same structure, is used to estimate the lattice specific heat to analyze the magnetic part. NpNiSn orders antiferromagnetically below K. In both compounds the antiferromagnetic order is not affected by magnetic fields up to 14T. [Copyright &y& Elsevier]

The ErNi1-xCuxAl compounds have been studied from the view of crystallographic structure and magnetic properties by means of X-ray and neutron diffraction, magnetization and heat capacity measurements. The hexagonal ZrNiAl-type crystal structure adopted by the parent compounds ErNiAl and ErCuAl is conserved over the entire composition range. The concentration dependence of lattice parameters shows a discontinuity between x=0.5 and 0.6 both in paramagnetic and magnetically ordered phase. The evolution of magnetism from antiferromagnetism (AF) with Er-moments within the basal plane in ErNiAl to the simple ferromagnetism (F) with moments along the c-axis in ErCuAl is rather complex. The AF ordering is characterized by a propagation vector (1/2,0,1/2) with moments within the basal plane in the low Cu-concentration region for x up to 0.40. An incommensurate component with Er-moments along c develops within the range of 0.20⩽x⩽0.40 and grows on account of the commensurate one. The ErNi0.5Cu0.5Al is a simple F with moments along c. For concentrations with x=0.6 and 0.8 signs of short-range ordering were revealed. [Copyright &y& Elsevier]

In this work we present the study of the part of Ce(Ni,Cu)Al series from the pure CeNiAl to 30% of copper concentration, which illustrates the transition from mixed-valence state of CeNiAl to the trivalent state in CeCuAl. The work is based on X-ray diffraction, magnetization and specific heat measurement. The results indicate smooth transition between the mixed-valence and trivalent cerium state. The specific-heat data reveal increase of the Sommerfeld γ coefficient with copper concentration. [ABSTRACT FROM AUTHOR]

We have studied the development of the magnetocaloric effect in the (Tb,Y)NiAl and TbNi(Al,In) series as determined from magnetization measurements. The transition from antiferromagnetic order in TbNiAl to ferromagnetic order in Tb0.7Y0.3NiAl is accompanied by increase of the maximum entropy change from - 4.1 to - 4.4 J kg-1 K-1. In the TbNi(Al,In) series, the change of uniaxial anisotropy in TbNiAl to the easy-plane anisotropy in TbNiIn leads to broadening of the magnetocaloric effect accompanied with large increase of the relative cooling power from 66 to 120 J kg-1. [ABSTRACT FROM AUTHOR]

The magnetic phase transitions in TbNiAl1-xInx compounds were investigated by ac-susceptibility measurements. Our data reveal magnetic ordering with transition temperatures between 40 and 70 K, depending on the In concentration. All the studied compounds exhibit two or more phase transitions accompanied by distinct anomalies in the real and imaginary part of the ac-susceptibility. The paramagnetic Curie temperatures remain positive in the whole series. [ABSTRACT FROM AUTHOR]

Abstract: We present results of specific-heat measurements on several AnTX compounds with the hexagonal ZrNiAl-type structure. All the studied neptunium materials order antiferromagnetically with highest K in NpIrAl. On contrary, the Pu-based isostructural materials do not show any phase transitions down to lowest achievable temperatures. The coefficient of the electronic specific heat is moderately enhanced ( mJK mol). [Copyright &y& Elsevier]

The magnetic structure in TbPdIn was investigated by neutron diffraction experiments. The results reveal a long-range magnetic structure with propagation vector (0,0,0) and the Tb moments forming a non-collinear structure within the basal plane that is unchanged over the whole temperature region below the ordering temperature of 66 K. [ABSTRACT FROM AUTHOR]

Abstract: The magnetic properties of PuGa2 were studied by susceptibility, magnetisation and specific heat measurements. Contrary to the uranium and neptunium counterparts, which order ferromagnetically, PuGa2 orders antiferromagnetically below T N =74K. The antiferromagnetic order is not affected by magnetic fields up to 9T. Similarly to UGa2, the small value of the electronic specific heat (γ =12mJmol−1 K−2) reflects a low density of states at the Fermi level. [Copyright &y& Elsevier]

Abstract: Recently, an attention has been paid to outstanding magnetic properties of martensitic phase of the Co-doped Heusler Ni2MnGa alloys with a paramagnetic gap that can be tuned by composition. We have prepared polycrystalline sample of Co doped Ni2MnGa alloy, Ni43Co7Mn31Ga19, with the very small amount of Er (0.1at.%). By the EDX analysis, a distinct segregation of Er was discovered in Er-rich phase while the main bulk material of the microcrystals was totally Er-free. Saturated magnetization M(5K)=3.27μB/f.u. and the Curie temperatures of austenite phase, were observed by a SQUID magnetometer on annealed sample and the standard magnetocaloric effect at vicinity of was measured by direct method with ΔT =0.6K. Magnetic susceptibility obeys nicely the Curie-Weiss law with paramagnetic moment of μ eff =5.09μB/f.u. above . However in the pronounced contrast with the Er-free alloys, both, the paramagnetic gap and mainly the martensitic transitions were not observed in the Er conditioned Ni43Co7Mn31Ga19 sample. [Copyright &y& Elsevier]