ESRF News March 2026

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March 2026 ESRFnews

Reheated glass doesn ’ t forget

EBS - enabled experiments have shown

that metallic glasses can retain a

memory of pressure treatment even

after reheating . The results challenge

long - standing assumptions about how

glasses return to equilibrium , and

demonstrate the value of combining

advanced diffraction and coherent

X - ray techniques .

Metallic glasses are fast - cooled

alloys that conduct like metals but

lack crystalline order . They are

attractive engineering materials

because of their strength , elasticity

and resistance to corrosion , but their

atomic structure remains difficult to

probe – particularly under pressure .

To explore this , a team including

Beatrice Ruta of the CNRS

Institut Néel in Grenoble subjected

a platinum – copper – nickel –

phosphorus metallic glass to pressures

of 5 – 10 GPa , before reheating

samples either above or just below

the glass transition temperature and

then releasing the pressure . Previous

studies had suggested that , strangely ,

such treatments can leave glasses in a

more “ liquid - like ” state , but the origin

of this effect was unclear .

Using high - energy X - ray diffraction

at ID15A , X - ray photon correlation

spectroscopy at ID10 and fast

differential scanning calorimetry , the

team showed that the pressured glass

expands and contracts differently at

different length scales – an effect that

conventional X - ray analysis can

miss . “ A [ single ] structural marker

obtained from XRD ( the position

of the first sharp diffraction peak )

cannot be connected strictly to the

macroscopic density , as is commonly

accepted , ” says Ruta .

The biggest surprise came when the

pressure - treated glass was reheated

at ambient conditions . Rather than

relaxing back to an ordinary liquid

on crossing the glass transition

temperature , the atoms followed a

much slower relaxation pathway ,

effectively retaining a memory of the

earlier pressure treatment ( Mater .

Today 92 304 ) . “ This was extremely

surprising , as the loss of the glass

history upon equilibration is a

paradigm of the glass / liquid state , ”

Ruta says .

Ruta believes the results relied

critically on the EBS . “ With an

increase of the coherent flux by

two orders of magnitude , we could

characterise the atomic mobility with

unprecedented quality , ” she says .

The findings also hint that pressure

treatments could one day help slow

the ageing of metallic glasses , which

can otherwise relax , crystallise and

fracture over time .

• For other ways the ESRF is

transforming high - pressure research ,

see the feature on p16 .

In situ X - ray scattering experiments

at the ESRF show that the fate of a

crystal can be determined long before

it actually forms . The work reveals

that additives can steer crystallisation

pathways at the prenucleation stage ,

before any ordered solid exists .

Alexander Van Driessche at the

University of Grenada in Spain and

colleagues studied the nucleation

of portlandite and gypsum ( pictured

above ) – two minerals central to

cement chemistry – using several

techniques in situ . By combining high -

energy X - ray scattering at the ESRF ’ s

ID15A beamline with electrochemical

sensors and controlled titration , the

team was able to follow crystallisation

continuously , from the earliest ion

associations through amorphous

intermediates , all the way to crystalline

phases .

The researchers tracked the

entire nucleation process , from

prenucleation clusters onwards .

The experiments were particularly

challenging because the solutions

were extremely dilute , prompting

the development of a new correction

method to recover weak scattering

signals hidden by detector effects .

The results revealed that additives

act in mineral - specific ways , primarily

during the prenucleation stage , and can

simultaneously delay some steps while

accelerating others . Portlandite was

found to evolve gradually from disorder

to order while gypsum underwent a

much more abrupt crystallisation Nat

Commun doi 10 1038 s41467 026

68583 1

Our work shows that by watching

every stage of crystal formation in real

time we can start designing additives

that guide the process instead of just

reacting to it says Van Driessche

It s a step towards making industrial

crystallisation smarter and hopefully

more sustainable

Left A schematic energy landscape shows how compressing a metallic glass below its glass transition

HPA can push it into a different higher energy amorphous state on reheating at ambient pressure it does not

fully relax back as expected Right Measured structural relaxation times τ

in the supercooled liquid show

that pressure treated samples 5 and 10 GPa follow a different dynamical trend from the ambient reference

consistent with liquid state behaviour that still reflects the earlier pressure history

M A T E R . T O D A Y 9 2 3 0 4 / C C B Y 4 . 0

Crystal ’ s fate is determined

before birth

100

P o t e n t i a l e n e r g y

liquid

dynamics

– 11K

– 7K

1 atm

HPA 5

GPa

HPA 10

GPa

( s )

1 86 1 88 1 90

1000 T K

1 92 1 94 1 96 1 98 2 00

530 535 525 520

T ( K )

515 510 505 500

< 0

Coordinates

HPA

1 atm , HT

sample

Lorem

D I D I E R D E S C O U E N S / C C B Y 4 . 0