# Towards mechanomagnetics in elastic crystals: insights from [Cu(acac)$_2$]

## TL;DR

This study predicts that bending an elastic crystal of uacac significantly alters its magnetic properties, with potential implications for mechanomagnetic applications, though practical use remains limited due to low ordering temperatures.

## Contribution

It introduces the concept of mechanomagnetics in elastic crystals and shows how bending dramatically affects magnetic ordering temperatures in uacac.

## Key findings

- Bending increases the magnetic ordering temperature by 24 orders of magnitude.
- uacac is an almost perfect Tomonaga-Luttinger liquid when unbent.
- Geometric frustration suppresses magnetic ordering and enhances sensitivity to bending.

## Abstract

We predict that the magnetic properties of \cuacac, an elastically flexible crystal, change dramatically when the crystal is bent. We find that unbent \cuacac\ is an almost perfect Tomonaga-Luttinger liquid. Broken-symmetry density functional calculations reveal that the magnetic exchange interactions along the chains is an order of magnitude larger than the interchain exchange. The geometrically frustrated interchain interactions cannot magnetically order the material at any experimentally accessible temperature. The ordering temperature ($T_N$), calculated from the chain random phase approximation, increases by approximately 24 orders of magnitude when the material is bent. We demonstrate that geometric frustration both suppresses $T_N$ and enhances the sensitivity of $T_N$ to bending. In \cuacac, $T_N$ is extremely sensitive to bending, but remains too low for practical applications, even when bent. Partially frustrated materials could achieve the balance of high $T_N$ and good sensitivity to bending required for practical applications of mechanomagnetic elastic crystals.