This dataset supports a study on voltage-driven magneto-ionic control of magnetization in CoFeN thin films, aimed at enabling energy-efficient, neuromorphic-inspired functionalities without the use of external magnetic fields. The purpose of the dataset is to provide comprehensive experimental data documenting the electric-field-induced magnetic evolution associated with planar N³⁻ ion migration and its cumulative, non-volatile effects on magnetization.

The dataset comprises raw and processed measurements obtained from magnetometry and magneto-optical characterization techniques, including voltage-dependent magnetization loops, remanent-state magnetic responses, and time- and history-dependent switching protocols. Data are organized to capture the influence of applied voltage amplitude, polarity, duration, and sequencing, as well as the role of prior electric and magnetic states. Where applicable, supporting structural or compositional characterization data are included to contextualize the magnetic behavior.

The scope of the dataset covers multiple experimental conditions designed to emulate synaptic-like potentiation and depression, as well as cumulative voltage-driven magnetization changes in the absence of an external magnetic field. This dataset is intended to facilitate reproducibility, comparative analysis, and further modeling of magneto-ionic and neuromorphic phenomena, and to serve as a reference for the development of voltage-controlled magnetic devices and brain-inspired computing architectures.

METHODOLOGICAL INFORMATION

1. Description of methods used for collection-generation of data: We used the Vibrarting sample magnetometry technique to obtain magnètic data. We used ThermoFisher Scientific, Glacios 200kV transmission electron microscope with extreme field emission gun (X-FEG) optics for TEM imaging.

2. Methods for processing the data: For hystereis loops the linear background was substracted and the magnètic moment was normalized by the volume assuming that the thickness was 50 nm and the surface was measured using Imagej. The magnetization vs time loops were also normalized by volume and the linear background was substracted form the signal where magnetix field is applied. The remanence part of the signal was only normalized by the volume. The TEM images from each píxel the spectra is obtained, the specific region for Nitrogen, Iron and Cobalt was selected and the background was substracted to asses the atòmic contribution in each píxel.

3. Instrument- or software- specific information needed to interpret the data: Origin, ImageJ and Digital micrograph

4. Instruments, calibration and standards information: We used the Vibrarting sample magnetometry technique to obtain magnètic data. It was calibrated using a níquel Standard provided by the company We used ThermoFisher Scientific, Glacios 200kV transmission electron microscope with extreme field emission gun (X-FEG) optics for TEM imaging.

5. Environmental or experimental conditions: The room temperature was always 22ºC