In this work, we present the arrangement of Fe3O4 magnetic nanoparticles into 3D linear chains and its effect on magnetic particle hyperthermia efficiency. The alignment has been performed under a 40 mT magnetic field in an agarose gel matrix. Two different sizes of magnetite nanoparticles, 10 and 40 nm, have been examined, exhibiting room temperature superparamagnetic and ferromagnetic behavior, in terms of DC magnetic field, respectively. The chain formation is experimentally visualized by scanning electron microscopy images. A molecular Dynamics anisotropic diffusion model that outlines the role of intrinsic particle properties and inter-particle distances on dipolar interactions has been used to simulate the chain formation process. The anisotropic character of the aligned samples is also reflected to ferromagnetic resonance and static magnetometry measurements. Compared to the non-aligned samples, magnetically aligned ones present enhanced heating efficiency increasing specific loss power value by a factor of two. Dipolar interactions are responsible for the chain formation of controllable density and thickness inducing shape anisotropy, which in turn enhances magnetic particle hyperthermia efficiency.

In 2017, we discovered quaternary i-MAX phases-atomically layered solids, where M is an early transition metal, A is an A group element, and X is C-with a (M 1 2/3 M 2 1/3)2AC chemistry, where the M 1 and M 2 atoms are in-plane ordered. Herein we report on the discovery of a class of magnetic i-MAX phases in which bi-layers of a quasi-2D magnetic frustrated triangular lattice overlays a Mo honeycomb arrangement and an Al Kagomé lattice. The chemistry of this family is (Mo2/3RE1/3)2AlC, and the rare earth elements, RE, are Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, and Lu. The magnetic properties were characterized and found to display a plethora of ground states, resulting from an interplay of competing magnetic interactions in the presence of magnetocrystalline anisotropy. This material is available free of charge via the Internet at http://pubs.acs.org.

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In 2013, a new class of inherently nanolaminated magnetic materials, the so called magnetic MAX phases, was discovered. Following predictive material stability calculations, the hexagonal Mn 2 GaC compound was synthesized as hetero-epitaxial films containing Mn as the exclusive M-element. Recent theoretical and experimental studies suggested a high magnetic ordering temperature and non-collinear antiferromagnetic (AFM) spin states as a result of competitive ferromagnetic and antiferromagnetic exchange interactions. In order to assess the potential for practical applications of Mn 2 GaC, we have studied the temperature-dependent magnetization, and the magnetoresistive, magnetostrictive as well as magnetocaloric properties of the compound. The material exhibits two magnetic phase transitions. The Néel temperature is T N ~ 507 K, at which the system changes from a collinear AFM state to the paramagnetic state. At T t = 214 K the material undergoes a first order magnetic phase transition from AFM at higher temperature to a non-collinear AFM spin structure. Both states show large uniaxial c-axis magnetostriction of 450 ppm. Remarkably, the magnetostriction changes sign, being compressive (negative) above T t and tensile (positive) below the T t . The sign change of the magnetostriction is accompanied by a sign change in the magnetoresistance indicating a coupling among the spin, lattice and electrical transport properties.Inherently nanolaminated M n+1 AX n (n = 1, 2, 3) compounds attract tremendous interest, since these materials provide the unique anisotropic structural and physical properties important for diverse applications 1,2 . These compounds, collectively known as MAX phases, are composed of an early transition metal (M), a p-element from the A-group elements (A) and X being either C or N. MAX phases have a hexagonal structure and belong to the space group P6 3 /mmc with the primitive unit cell given by 8 atoms: 4 M, 2 A and 2 X (for n = 1). These systems exhibit an atomically laminated structure composed of M-X-M (M 2 X) slabs interleaved by A-element atomic layers. The atomic layers are stacked along the c-axis. The layered, highly anisotropic crystal structure results in mechanical properties usually associated with ceramics, such as high stiffness, damage tolerance and resistance to corrosion and thermal shock 1,2 . The chemical bonding of the M, A and X elements is anisotropic and comprises metallic, covalent and ionic character 2 . The strong hybridization between d orbitals of the M-element and 2p states of the X-element results in directed covalent bonds along the M-X-M chains in basal planes 2,3 . The M-A bonding is generally weaker and accompanied by partial charge transfer from the M-element to the A-element, giving rise to the ionic contribution 2-4 . Metallic-like bonding between d states of the M-element occurs in the