# Magnetic field driven complex phase diagram of antiferromagnetic heavy-fermion superconductor Ce$_3$PtIn$_{11}$

## TL;DR

This study explores the complex magnetic phase diagram of the heavy-fermion superconductor Ce$_3$PtIn$_{11}$, revealing multiple magnetic transitions, field-stabilized phases, and evidence of unconventional superconductivity coexisting with magnetic order.

## Contribution

It provides a detailed experimental mapping of the magnetic phases and transitions in Ce$_3$PtIn$_{11}$ under various magnetic fields and temperatures, highlighting its unique coexistence of superconductivity and magnetic order.

## Key findings

- Identification of a complex magnetic phase diagram with multiple transitions.
- Observation of a prominent metamagnetic transition at low temperatures.
- Evidence supporting unconventional pairing in the superconducting phase.

## Abstract

We present the results of our comprehensive investigation on the antiferromagnetic heavy-fermion superconductor Ce$_3$PtIn$_{11}$ carried out by means of electrical transport, heat capacity and ac magnetic susceptibility measurements, performed on single-crystalline specimens down to 50 mK in external magnetic fields up to 9~T. Our experimental results elucidate a complex magnetic field -- temperature phase diagram which contains both first- and second-order field-induced magnetic transitions and highlights the emergence of field stabilized phases. Remarkably, a prominent metamagnetic transition was found to occur at low temperatures and strong magnetic fields. In turn, the results obtained in the superconducting phase of Ce$_3$PtIn$_{11}$ corroborate an unconventional nature of Cooper pairs formed by heavy quasiparticles. The compound is an almost unique example of a heavy fermion system in which superconductivity may coexist microscopically with magnetically ordered state.