Zr-based bulk metallic glass clamp cell for high-pressure inelastic neutron scattering

TL;DR

The paper tackles the challenge of high-pressure INS quality by developing a Zr-based bulk metallic glass hybrid clamp cell with a Zr-BMG inner sleeve and an Al outer body. The cell delivers higher neutron transmission (e.g., $\sim$33% at $2.96\ \mathrm{meV}$) and a clean, featureless background compared with conventional CuBe cells, as demonstrated by empty-cell measurements and a CsFeCl$_{3}$ test. INS on a Zr-BMG rod shows broad, amorphous-like spectra and a low-energy boson peak, while pressure calibration with NaCl confirms hydrostatic pressurization to ~1 GPa. These results establish Zr-BMG as a promising material for high-pressure INS, enabling more precise studies of magnetic and lattice excitations in quantum materials under pressure.

Abstract

We report the fabrication and characterization of a Zr-based bulk metallic glass (Zr-BMG) clamp cell designed for high-pressure inelastic neutron scattering (INS) measurements. The INS spectra of the empty cell exhibit broad and featureless backgrounds, reflecting the amorphous structure of the Zr-BMG. Test measurements using a reference sample, CsFeCl$_{3}$, confirm that the neutron transmission of the Zr-BMG cell is significantly higher than that of a conventional monobloc CuBe clamp cell. These results demonstrate that the Zr-BMG clamp cell provides both enhanced neutron transparency and a clean background profile, thereby advancing high-pressure INS studies.

Figures (8)

• Figure 1: Schematic view and photograph of the full assembled hybrid cylinder clamp cell used in the present study. The blue, green and gray components correspond to the Zr-BMG inner sleeve, the aluminum alloy (A7075) outer body, and the tungsten carbide piston and support spacers, respectively. The red components are the locking nuts fabricated from either aluminum alloy or CuBe alloy.
• Figure 2: (a) False-color plot of the INS spectra of the Zr-BMG measured with $E_{\rm i}=20.0$ meV at room temperature (R.T.). (b) Momentum-transfer profiles of the spectra at the elastic line integrated over $-0.5 \leq E \leq 0.5$ meV and the inelastic regime integrated over $4 \leq E \leq 16$ meV. For visibility, the elastic profile is scaled by a factor of 0.01, and the inelastic profile is vertically offset by 4. (c) Energy-transfer profile of the INS intensity integrated below 2 Å$^{-1}$.
• Figure 3: False-color plots of the INS spectra of the empty pressure cell measured with (a),(b) $E_{\rm i}=2.96$ meV, (c),(d) $E_{\rm i}=20.0$ meV, and (e),(f) $E_{\rm i}=55.6$ meV. Data were taken at $T=6$ K (upper panels) and at room temperature (R.T., lower panels).
• Figure 4: (a) Elastic line of the INS spectrum of the pressure cell (black symbols) and the Zr-BMG rod (red curve), measured at R.T. with $E_{\rm i}=20.0$ meV. The energy transfers are integrated over $-0.5\leq E \leq 0.5$ meV. The intensity of the Zr-BMG rod is scaled by an arbitrary factor for visibility. Blue and green arrows indicate nuclear Bragg peaks arising from the aluminum-alloy body and the PTFE capsule, respectively. (b) Momentum-transfer profiles of the INS intensities of the cell integrated over $4\leq E \leq 16$ meV at $T=6$ K (black circles) and R.T. (red circles).
• Figure 5: False-color plots of the INS spectra of CsFeCl$_{3}$ along the $[110]$ direction measured with $E_{\rm i}=2.96$ meV. Data were collected (a) without the pressure cell and (b) with the pressure cell. The momentum transfer perpendicular to the plot axis is integrated over $\pm0.1$ Å$^{-1}$.