Under normal conditions, magnetic materials go through a "thawing" transition as the temperature rises, making them nonmagnetic. Physicists typically consider materials as either having magnetic order or lacking it. Running thousands of computer simulations to show this helimagnets behavior explains how magnetic dipoles of atoms inside the material are arranged during the thawing transition.
An Exploration of a Strange Electronic Behavior
A kind of material that acts as "stacked pancakes of liquid magnetism" was discovered by researchers at Rice University and Ames Laboratory at Iowa State University. Experimental physicist, Makariy Tanatar of Ames National Laboratory at Iowa State University, observed mysterious electronic behavior in layered helimagnetic crystals. He collaborated with rice theoretical physicist Andriy Nevidomskyy to create a Monte Carlo computational model that can simulate the quantum behavior of atoms and electrons in layered materials.
This study published in Phys Org journal involves using materials made up of thousands of 2D crystals layered on each other like notebook pages. A lattice arrangement of atoms is formed in each crystal layer and scientists between and within the sheets model quantum interactions. The materials are magnetic in appearance at low temperatures and become nonmagnetic as the temperature begins to rise. The changes in the arrangement of magnetic dipoles upon warming cause these materials to arise in some helical magnets.
Tanatar discovered the signs that the thawing transition is related to a transitory phase where resistance and other electronic properties are affected by direction. The directional behavior called anisotropy is a trademark of many quantum materials, such as high-temperature superconductors.
Extremely low temperature at the bottom panel leads to the orderly arrangement of dipoles into magnetism. The dipoles get disordered in the top panel with high temperatures, and the materials become nonmagnetic. On the other hand, the intermediate temperature in the middle panel causes the pancakes of liquidlike magnetism to appear. In this panel, the magnetic interactions within horizontal 2D layers are stronger than vertical interactions between the layers.
Tanatar and Nevidomskyy's discovery has no immediate application yet, but it can provide an understanding of the unexplained behavior of anisotropic materials such as high-temperature superconductors.
A View of Anisotropic Materials
Anisotropic materials, also known as triclinic materials, are a type of media that can change or assume various properties in different directions. When it comes to magnetism, anisotropic magnets possess magnetic properties that depend on their magnetization direction. They are aligned in their magnetization direction when manufactured in the future. Since anisotropic magnets have a preferred magnetization direction, they cannot be magnetized outside this direction. This provides the advantage of having stronger magnetic properties than isotropic magnets or those with no preferred magnetization direction.
The nature of anisotropic superconducting transition remains a mystery for experts. As two-dimensional superconductivity is an ideal environment for strange quantum phenomena, earlier studies were done to understand the quantum phase transitions in 2D disordered systems. Superconductivity shows remarkable robustness against the in-plane magnetic field and its anisotropy.
To further understand the sensitivity of superconducting order parameters to magnetic field orientations, physicists explore this transport anisotropy with different orientations in the magnetic field.
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