Ferromagnetic Phase Transition of DPPH Induced by a Helical Magnetic Field

TL;DR

This study demonstrates a room-temperature ferromagnetic phase transition in DPPH induced by a helical magnetic field at the Magic Angle, with the material remaining ferromagnetic for at least an hour post-experiment.

Contribution

The paper introduces a novel experimental setup that induces ferromagnetism in DPPH using a specific helical magnetic field configuration at the Magic Angle.

Findings

DPPH transitioned from paramagnetic to ferromagnetic at room temperature.

The ferromagnetic state persisted for at least one hour after the experiment.

Magnetic permeability increased by a thousand-fold, reaching approximately 1.4.

Abstract

We report the results and unique instrument configuration of a novel experiment in which we successfully transitioned a DPPH sample from its natural paramagnetic state and essentially a non-magnetic material to a ferromagnetic state at room temperature. This was achieved using a specifically applied helical flux magnetic field. The DPPH sample (2,2-diphenyl-1-picrylhydrazyl) remained ferromagnetic for at least one hour after the experiment, indicating that a transformation in the material was induced by the external field rather than being merely a temporary magnetic phase transition observed only during the experiment. The external magnetic field used had a helical pitch angle of approximately $54.7{\deg}$, known mathematically as the Magic Angle, relative to the +z-axis, which is aligned with the normal S to N external field's magnetic moment vector. Based on the phenomenology of the experiment and results, we suggest that this specific magic angle corresponding to the known quantization precession spin angle of free electrons under a homogeneous straight flux magnetic field potentially enhances the percentage of unpaired valence electrons within the DPPH material, allowing them to align in parallel with the applied external field. Typically, in paramagnetic materials, the distribution of unpaired electrons' quantum spins relative to an external field is nearly random, showing roughly a 50% chance of either parallel or antiparallel alignment. Only a slight majority preference exists in one alignment direction due to the Boltzmann thermal distribution, which contributes to the paramagnetic nature of these materials. In our measurements, we found that the induced ferromagnetism of the DPPH sample resulted in an abnormal thousand-fold decimal value increase in relative magnetic permeability at ${\mu}{\approx}1.4$, compared to its typical paramagnetic value of $1.0001$ for this material.