The crystal chemistry of binary and ternary intermetallic compounds with tetragonal U 3 Si 2 or Zr 3 Al 2 type structure is reviewed. Besides the preparation techniques and crystal chemistry, we especially focus on the structure-property relations and chemical bonding peculiarities.

Intermetallic compounds with ordered U3Si2 or Zr3Al2 type structure – crystal chemistry, chemical bonding and physical properties

Along with pressure and temperature, the magnetic field is one of the physical parameters that are used for the investigation of matter. It is an important tool for investigating magnetic and electronic properties from both the microscopic and macroscopic points of view. The interaction energy of a substance with a magnetic field, i.e. Zeeman energy or Landau energy, is small even at a field of 2 T as can be provided by a conventional electromagnet. Compared with the inner energies of a substance, magnetic fields as high as possible have been required for obtaining fine and detailed information on the internal structure and energy states. Due to the strong Maxwell stress, however, it is quite difficult to obtain a magnetic field higher than 50 T and much effort has been dedicated to the development of magnets ever since the laboratory electromagnet was invented.The purpose of this paper is to describe the physical effects that have been investigated and the phenomena that have been revealed using high magnetic fields, as well as the development of magnet technology and measurement technology. In addition, application to materials processing is mentioned as an active application of high magnetic fields.

https://iopscience.iop.org/article/10.1088/0034-4885/67/11/R02/pdf

Physics in high magnetic fields

Anomalous Metamagnetism in the Low Carrier Density Kondo Lattice YbRh3Si7

${\mathrm{U}}_{2}{\mathrm{Pd}}_{2}\mathrm{In}$ crystallizes in the tetragonal ${\mathrm{U}}_{3}{\mathrm{Si}}_{2}$ structure and it orders antiferromagnetically below ${T}_{\mathrm{N}}=38(1)\mathrm{K}.$ ${\mathrm{U}}_{3}{\mathrm{Si}}_{2}$ exhibits a complex noncollinear ground state with U moments confined in zero magnetic field to the tetragonal basal plane. Upon application of magnetic field at low temperatures, magnetization measurements suggest different field-induced magnetic structures for field applied along the [100] and [110] directions above 29 T and 26 T, respectively. Neutron-diffraction studies in fields up to 17 T and at 33 K reveal a magnetic structure that agrees with the theoretical predictions for low temperatures. Our results demonstrate the importance of hybridization-induced magnetocrystalline anisotropy that locks U moments in ${\mathrm{U}}_{2}{\mathrm{Pd}}_{2}\mathrm{In}$ in the [110]-type mirror planes.

Neutron diffraction and magnetization studies of U 2 Pd 2 In single crystals in high magnetic fields

Magnetic phase diagram of the antiferromagnet U2Rh2Pb

U 2 Pd 2 In exhibits antiferromagnetic (AF) order below T N =37 K with a non-collinear magnetic structure of U moments of ≈1.6 μ B /U confined to the basal plane of the tetragonal structure. At 4.2 K it exhibits a metamagnetic transition (MT) around 26 T. Previous high-field magnetization measurements on powder samples revealed that the fixed-powder magnetization attains above MT a higher value than the free-powder sample. The temperature dependence of susceptibility of a single crystal shows crossing of the basal plane and the c -axis signals below T N , the latter one dominating at low T . We present magnetization data obtained on single crystals in fields up to 55 T applied in various crystallographic directions. The observed magnetic anisotropy is attributed to the anisotropic 5f-ligand hybridization, which is forcing the U moments to orient in particular directions. The MT can be induced by a field applied within the basal plane but not in fields up to 55 T along the c -axis.

Metamagnetic transition in U2Pd2In

We present measurements of the de Haas–van Alphen effect in the heavy fermion compounds CeAl2 and CeRu2Si2. These were carried out at the NHMFL in Los Alamos in 60 T pulsed fields and at temperatures down to 340 mK. In CeAl2 with B parallel to [1 1 1], we have observed two cyclotron orbits with dHvA frequencies of 5.41 and 6.40 kT. The associated cyclotron masses are significantly lower than those reported by other groups in static fields up to 13 T. The cyclotron mass associated with the 6.40 kT orbit was studied in detail. It is field dependent and decreases from m*=4.80 m e at 26.6 T to m*=3.13 m e at 53.2 T. In CeRu2Si2, we have observed with B ∥[0 0 1] three low-frequency orbits with frequencies of 0.64, 1.06 and 1.11 kT, in good agreement with the previously reported β′, γ′ and δ orbits. We describe the observed evolution of the cyclotron mass as a function of the magnetic field.

de Haas–van Alphen studies of the heavy fermions CeAl2 and CeRu2Si2

We have studied the cyclotron mass of the heavy fermion compound CeAl 2 by measuring the de Haas–van Alphen effect in pulsed magnetic fields up to 52 T and at temperatures down to 1.7 K. With the field parallel to [1 1 1] we find two high-frequency extremal orbits with frequencies of 6.40 and 5.41 kT. These values are close to those reported in the literature for the same field orientation. We observe a striking field dependence of the cyclotron mass of the 6.40 kT orbit, similar to the mass decrease observed in CeB 6 . The cyclotron mass changes from m ∗ /m e =(4.4±0.7) at 35 T to m ∗ /m e =(2.0±1.1) at 49 T. This should be compared with the value m ∗ /m e =(14.7±0.5) reported below 13 T.

E.G. Haanappel

Papers

Metamagnetic transition in U2Pd2In

de Haas–van Alphen studies of the heavy fermions CeAl2 and CeRu2Si2

Field-dependent cyclotron mass of CeAl2