Data Documentation for research paper "Hyperbolic Bloch points in ferrimagnetic exchange spring"
 
General Information
Files include Transmission X-ray Microscopy data from a GdCo/NdCo/GdCo trilayer as described in the research paper 
"Hyperbolic Bloch points in ferrimagnetic exchange spring” Results in Physics (2024) by Hermosa et al.

Name of dataset: 
DATA from research paper "Hyperbolic Bloch points in ferrimagnetic exchange spring” Results in Physics (2024) 
by Hermosa et al

Name of data files in data set:
Tiltseries1.tlt; Tiltseries1_M4.mrc; Tiltseries1_M5.mrc; Tiltseries2.tlt; Tiltseries2_M4.mrc; Tiltseries2_M5.mrc

Dataset language:
English

Date the data set was last modified:
4/12/2023

Funder:
The ALBA Synchrotron is funded by the Ministry of Research and Innovation of Spain, by the Generalitat de Catalunya and 
by European FEDER funds. This work has been supported by Spanish MCIN/AEI/10.13039/501100011033/FEDER,UE under grants 
PID2019-104604RB and PID2022-136784NB and by Asturias FICYT under grant AYUD/2021/51185 with the support of FEDER funds.

How to cite data:
With the doi generated

Methodology for data collection: 
The sample was mounted on the high precision rotary stage of the full field X-ray transmission microscope at the MISTRAL beamline of the ALBA Synchrotron. 
One hundred nm diameter gold nanoparticles were sprinkled onto its surface to serve as fiducials for accurate projection 
alignment to a common rotation axis prior to the tomography reconstruction. The sample was illuminated with circularly 
polarized X-rays to exploit magnetic contrast from X-ray magnetic circular dichroism at the Gd M4 (1221.9 eV) and 
Gd M5 (1189.6 eV) absorption edges. The sample was rotated around an axis parallel to the sample surface to acquire a 
tilt series of images (at 2° intervals in the angular range \theta=±26° and at 1° intervals in the angular ranges
 [-55°,-26°] and [26°,55°]). As the tomographic reconstruction requires two orthogonal tilt series, the sample was 
rotated \phi~ 95° in-plane before acquiring the second tilt series. Typical exposition times are around 5 s. For larger angles exposition times were increased to keep similar 
signal-to-noise ratios. Since the Gd M4 edge and the Gd M5 edge have opposite signs of the X-ray magnetic circular 
dichroic factor, images have been acquired at both edges at each (\theta,\phi) orientation. Adding or subtracting the 
logarithm of individual transmittance images at M4 and M5 edges allows us to obtain the charge (TXM) and magnetic (MTXM) 
contrast images.

Data collector(s): 
Javier Hermosa, Aurelio Hierro, Carlos Quirós, Andrea Sorrentino, Eva Pereiro and Salvador Ferrer

Date of data collection: 
30/10/2019-3/11/2019

Person to contact with questions: 
javihermosa94@gmail.com, hierroaurelio@uniovi.es, mvelez@uniovi.es

Data entry: 
5/04/2024

Software (including version #) used to prepare data set: 
MATLAB 2023a, IMOD 4.9.12


Data processing that was performed: 
The images acquired at Gd M4 and at Gd M5 absorption edges were corrected removing flat-field and dark-field contributions
and were subsequently averaged and grouped in .mrc files for each tilt series.

Variables
Each .mrc file (81 arrays of 877x877 numbers) contains 81 X-ray transmittance images with 877x877 pixels. 
The .tlt files have 81 numbers, corresponding to the angles of the images in the .mrc files expressed in degrees. 
Pixel size is 13.5 nm

File Overview
X-ray transmittance images from two tilt series are included in .mrc format, in separated folders 
("Tilt series 1" and "Tilt series 2"). 
Each folder contains data acquired at Gd M4 and Gd M5 absorption edges at each angular orientation 
("Tiltseries#_M4.mrc" and "Tiltseries#_M5.mrc").
The two tilt series are collected at perpendicular axial angles as defined in the scientific article by
Hermosa et al "Hyperbolic Bloch points in ferrimagnetic exchange spring" Results in Physics (2024).
The folder "Tilt series 1" has two .mrc files (acquired at Gd M4 and Gd M5 absorption edges), 
called "Tiltseries1_M4.mrc" and "Tiltseries1_M5.mrc", each of them with 81 images 877x877 pixels.
It also includes a .tlt file (readable with Matlab), "Tiltseries1.tlt", with the 81 angles of each of the .mrc files.
The folder "Tilt series 2" has two .mrc files (acquired at Gd M4 and Gd M5 absorption edges), 
called "Tiltseries2_M4.mrc" and "Tiltseries2_M5.mrc", each of them with 81 images 877x877 pixels.
It also includes a .tlt file (readable with Matlab), "Tiltseries2.tlt", with the 81 angles of the .mrc files.