Successive magnetic transitions in TbNiAl2 studied by neutron diffraction

6th Meeting of the Spanish Neutron Scattering Association

Rojas, D.P.^1 ; Marcos, J. Sánchez^2 ; Fernández, J. Rodríguez^3

Departamento de Física e Instalaciones, ETSAM, Universidad Politécnica de Madrid, Av. Juan Herrera 4, Madrid

28040, Spain^1

Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, c/ Francisco Tomas y Valiente 7, Madrid

28049, Spain^2

DCITIMAC, Facultad de Ciencias, Universidad de Cantabria, Santander

39005, Spain^3

关键词: Antiferromagnetic characters;    Antiferromagnetics;    Incommensurate magnetic structures;    Macroscopic measurements;    Magnetic transitions;    Orthorhombic structures;    Temperature decrease;    X-Ray and neutron diffraction;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/549/1/012020/pdf
DOI  :  10.1088/1742-6596/549/1/012020

来源: IOP

【 摘 要 】

We report measurements of DC (AC) magnetic susceptibility and neutron diffraction on TbNiAl2alloy. The Rietveld refinements of the x-ray and neutron diffraction data are consistent with an orthorhombic structure of the type MgCuAl2(space group Cmcm). The results of DC (AC)- magnetic susceptibility show two successive magnetic transitions at 20 K and 11.7 K with antiferromagnetic and ferromagnetic (or ferrimagnetic) features, respectively. On the other hand, neutron diffraction patterns show that, below 20 K and down to 12 K, new reflexions appear, confirming the antiferromagnetic character of the transition observed in the macroscopic measurements. Also, at least one of these new reflexions, located at Q 1.2 Å-1, shifts to higher angles when the temperature decreases, indicating an incommensurate magnetic structure. Below 11 K, many reflexions disappear and new reflexions increase, evidencing a new magnetic transition.